Understanding Computer Viruses and Malware: Protection and Removal Guide

Your computer slows down mysteriously. Pop-up ads appear constantly. Antivirus warnings flash. Your homepage changed without permission. These are signs of malware infection.

At SnapFixRepairs in Oldham, we clean infected computers weekly. Most infections are preventable with basic security practices. Here's everything you need to know.

Types of Threats

Viruses

Self-replicating programs that spread between computers. Attach to files and programs, spreading when you share files.

Modern viruses are less common than other malware types, but the term "virus" is used generically for all malware.

Malware

Umbrella term for all malicious software. Includes viruses, trojans, spyware, adware, and more.

Ransomware

Encrypts all your files and demands payment for the decryption key. Devastating without backups.

Growing threat. Targets both individuals and businesses.

Adware

Displays unwanted advertisements constantly. Pop-ups, banners, browser redirects.

Less dangerous than ransomware but extremely annoying.

Spyware

Monitors your activity and steals information. Records passwords, browsing habits, and personal data.

Often includes keyloggers that record everything you type.

Trojans

Disguises as legitimate software but contains malicious code. Named after the Trojan Horse.

Tricks users into installing by appearing harmless or useful.

Browser Hijackers

Changes browser homepage, search engine, and settings. Redirects searches to advertising sites.

Difficult to remove once installed.

Cryptocurrency Miners

Uses your computer's processing power to mine cryptocurrency for attackers.

Slows computer dramatically, increases electricity costs, wears out components faster.

Potentially Unwanted Programs (PUPs)

Not technically malware but unwanted software bundled with legitimate downloads.

Toolbars, browser extensions, optimization tools that don't optimize anything.

How You Get Infected

Downloading Free Software

Free software often bundles malware in installers. During installation, pre-checked boxes install unwanted programs.

"Cracked" or Pirated Software

Illegal software downloads are malware goldmines. Torrents, crack files, and key generators frequently contain trojans.

Fake Download Buttons

Websites with multiple "Download" buttons. Real download is small, fake buttons are large ads.

Clicking wrong button downloads malware instead of intended file.

Email Attachments

Opening attachments from unknown senders. Even attachments appearing from known senders might be spoofed.

Phishing Links

Emails or messages with links to fake websites designed to steal information or download malware.

Appear legitimate (bank, PayPal, Amazon) but URLs are slightly different.

Fake Tech Support

Pop-ups claiming computer is infected, instructing you to call "support." They install malware or charge for unnecessary services.

Real antivirus never displays phone numbers in warnings.

USB Drives

Infected USB drives spread malware when plugged into computers.

Found USB drives in public places are especially risky.

Software Update Tricks

Fake update notifications for Java, Flash, or other software. Downloads malware instead.

Compromised Websites

Legitimate websites sometimes get hacked and serve malware to visitors.

Less common but happens to even major sites occasionally.

Signs of Infection

Performance Problems

Computer dramatically slower than usual. Programs take forever to open.

High CPU usage when you're not doing anything intensive.

Pop-Up Ads

Constant pop-up advertisements, even when browser is closed.

Ads on websites that normally don't have ads.

Browser Changes

Homepage changed without your permission.

Different search engine appears.

New toolbars you didn't install.

Strange Programs

Programs you don't remember installing.

Programs that start automatically with Windows.

Antivirus Disabled

Your antivirus software stops working or can't update.

Malware often disables security software first.

Network Activity

Internet constantly busy even when you're not doing anything.

Indicates malware communicating with remote servers.

Ransomware Messages

Screen locked with message demanding payment.

All your files have strange extensions (.locked, .encrypted, etc.).

Friends Report Spam from Your Accounts

Your email or social media accounts send spam to contacts.

Indicates account compromise (change passwords immediately).

Prevention - Best Practices

Use Antivirus Software

Windows Defender (built into Windows 10/11): Actually quite good now. Adequate protection for most users.

Enable real-time protection and keep it updated.

Third-Party Options:

• Bitdefender (excellent protection, low system impact)
• ESET (very good, lightweight)
• Kaspersky (strong protection, more resource-heavy)
• Norton (solid protection, can be annoying with popups)

Free options:

• Avast (decent but shows ads)
• AVG (same company as Avast)

Avoid:

• Multiple antivirus programs simultaneously (causes conflicts)
• Unknown free antivirus (some are malware themselves)

Keep Windows Updated

Windows updates include critical security patches.

Enable automatic updates: Settings → Update & Security → Windows Update

Hackers exploit known vulnerabilities. Updates close these security holes.

Keep Programs Updated

Browsers (Chrome, Firefox, Edge): Update frequently, they auto-update usually

Java: Update or uninstall if you don't use it (major security risk)

Adobe Reader: Keep current or switch to browser PDF viewing

Other software: Check for updates monthly

Be Skeptical of Downloads

Only download software from official sources:

• Software manufacturer websites
• Microsoft Store
• Known legitimate sources

Avoid:

• Download sites (Softonic, Download.com, etc.)
• Torrent sites
• Random search results promising free software

Read Installation Screens

During software installation:

• Read each screen carefully
• Uncheck any optional software offers
• Choose "Custom" or "Advanced" installation
• Decline toolbars, browser changes, additional software

Don't Click Email Links Randomly

Hover over links to see actual URL before clicking.

If email seems suspicious, visit website directly rather than clicking link.

Verify sender address carefully (scammers use similar-looking addresses).

Use Strong Passwords

Different passwords for different accounts.

Use password manager (LastPass, 1Password, Bitwarden) to generate and store complex passwords.

Enable two-factor authentication wherever available.

Be Careful with USB Drives

Scan USB drives with antivirus before opening files.

Never use found USB drives without scanning.

Regular Backups

Backups don't prevent infection but protect against ransomware.

If ransomware encrypts files, restore from backup instead of paying ransom.

Browser Extensions

Install:

• uBlock Origin (blocks ads and malicious sites)
• HTTPS Everywhere (forces secure connections)

Be cautious with: Any browser extension requesting broad permissions.

Remove extensions you don't actively use.

Removing Malware Yourself

Step 1: Disconnect from Internet

Prevents malware from spreading or communicating with attackers.

Unplug ethernet or disable WiFi.

Step 2: Boot into Safe Mode

Safe Mode loads Windows with minimal drivers, preventing most malware from running.

Windows 10/11:

1. Hold Shift while clicking Restart
2. Troubleshoot → Advanced Options → Startup Settings → Restart
3. Press 4 for Safe Mode with Networking

Step 3: Delete Temporary Files

Free up space and remove some malware:

1. Search for "Disk Cleanup"
2. Select C: drive
3. Check all boxes
4. Click "Clean up system files"
5. Delete

Step 4: Run Windows Defender

Even if you use different antivirus, run Defender scan in Safe Mode:

1. Windows Security → Virus & threat protection
2. Scan options
3. Full scan
4. Scan now

Takes 30-120 minutes.

Step 5: Run Malwarebytes

Download Malwarebytes Free (malwarebytes.com) on clean computer.

Transfer to infected computer via USB.

Install and run full scan.

Malwarebytes catches what traditional antivirus misses.

Step 6: Check Installed Programs

Settings → Apps → Apps & features

Remove anything:

• You don't recognize
• Installed recently when problems started
• Has suspicious names
• Related to toolbars or optimization

Step 7: Check Browser Extensions

Chrome: Three dots → More tools → Extensions Firefox: Three lines → Add-ons → Extensions Edge: Three dots → Extensions

Remove unfamiliar or suspicious extensions.

Step 8: Reset Browser Settings

Chrome: Settings → Advanced → Reset settings → Restore settings to original defaults

Firefox: Help → More troubleshooting information → Refresh Firefox

Edge: Settings → Reset settings → Restore settings to their default values

Step 9: Check Startup Programs

Press Ctrl+Shift+Esc → Startup tab

Disable anything suspicious or unfamiliar.

Step 10: Run AdwCleaner

Download AdwCleaner (free from Malwarebytes).

Specifically targets adware and PUPs.

Run scan and clean.

Step 11: Change Passwords

After cleaning, change passwords for:

• Email accounts
• Banking
• Important accounts

Do this from different device if possible (in case keylogger remains).

Stubborn Infections

If malware persists after trying above:

Some malware is extremely persistent and resists removal.

Nuclear option: Windows Reset

Wipes computer and reinstalls Windows cleanly.

Settings → Update & Security → Recovery → Reset this PC

Choose "Remove everything" for thorough cleaning.

Warning: Backs up nothing. Ensure important files are backed up elsewhere first.

After reset, you'll reinstall programs and restore files from backup.

Ransomware - Special Case

If you get ransomware:

Don't pay the ransom. Payment doesn't guarantee file recovery. Encourages attackers.

Disconnect immediately to prevent spread to other computers/drives.

Check for decryptors: Visit nomoreransom.org - free decryption tools for some ransomware types.

Restore from backups if you have them (this is why backups matter!).

Professional help: Call SnapFixRepairs or fill out our form. We sometimes decrypt or recover files, depending on ransomware type.

When to Get Professional Help

Infection won't remove despite trying all DIY steps.

Ransomware - professional tools sometimes decrypt without paying ransom.

Data at risk - infected computer contains critical files with no backup.

No confidence in DIY - worried about making things worse.

Business computer - downtime costs money, professional removal is faster.

Banking/sensitive information accessed - professional verification ensures all malware removed.

SnapFixRepairs Malware Removal

Remote Malware Removal: £60-£100

For software-based infections, we connect remotely to your computer and clean thoroughly:

• Deep scan with professional tools
• Remove malware, adware, PUPs
• Browser cleaning and reset
• Windows optimization post-cleaning
• Security software setup

Usually completes within 2-4 hours.

Advanced Malware Removal: £80-£150

For stubborn infections requiring offline scanning or extensive cleaning.

Includes:

• Bootable antivirus scans
• Rootkit removal
• Registry cleaning
• Complete system verification
• Security recommendations

Ransomware Assessment: £80-£200

Ransomware situations assessed individually.

We:

• Identify ransomware type
• Check for available decryptors
• Attempt file recovery
• Assess damage
• Provide recommendations

No guarantees with ransomware (depends on type), but we try everything before suggesting last resort options.

Contact Method:

Call SnapFixRepairs or fill out our online form describing your symptoms.

For remote removal, we'll schedule time and send connection details.

Most infections cleaned same-day.

Prevention Service

Security Checkup: £40-£60

We configure your computer for maximum security:

• Install/configure quality antivirus
• Remove existing malware/bloatware
• Configure Windows security settings
• Install ad blockers
• Set up automatic updates
• Security best practices training

One-time service that dramatically reduces future infection risk.

Cost of Prevention vs Cure

Prevention costs: Good antivirus: £20-£40/year or free (Windows Defender) Time to practice safe computing: Free Security checkup: £40-£60 one-time

Cure costs: Malware removal: £60-£150 Lost productivity: Hours to days Potential data loss: Priceless Ransomware payment: £300-£5,000+ (don't pay!) Professional data recovery: £300-£1,500

Prevention is dramatically cheaper and less stressful.

Key Takeaways

Prevention best practices:

1. Keep Windows and software updated
2. Use antivirus (Windows Defender minimum)
3. Be skeptical of downloads and email links
4. Read installation screens carefully
5. Maintain regular backups

If infected:

1. Disconnect from internet
2. Boot Safe Mode
3. Run antivirus scans
4. Remove suspicious programs
5. Reset browsers
6. Change passwords after cleaning

Get help if:

• DIY removal fails
• Ransomware infection
• Critical data at risk
• Need certainty all malware is removed

Call SnapFixRepairs or fill out our online form for professional malware removal and security setup.

Don't wait until infection happens - preventive security setup protects you now.