What Is Malware?
Malware is a broad term for any software designed to harm your computer or steal your information. It includes viruses (programs that spread and damage files), spyware (programs that secretly monitor what you do), ransomware (programs that lock your files and demand payment), and adware (programs that flood you with unwanted ads). You do not have to do anything obviously wrong to get infected — malware can arrive through email attachments, fake software downloads, malicious websites, or even legitimate websites that have been compromised.
Warning Signs Your Computer May Be Infected
Malware often tries to stay hidden, but most infections leave clues. Watch for these signs.
- The computer has become noticeably slower for no obvious reason
- Pop-up ads appear constantly, even when you are not browsing the web
- Your browser homepage or default search engine changed without your permission
- Programs open or close on their own
- You see unfamiliar programs in your list of installed apps
- Your antivirus has been disabled and you cannot turn it back on
- Friends report receiving strange emails or messages from your account
- You are redirected to unexpected websites when you click links
What to Do Right Now If You Suspect an Infection
If you think your computer is infected, act quickly. The longer malware runs, the more damage it can do.
- 1Disconnect from the internet by unplugging your network cable or turning off Wi-Fi — this stops malware from sending your data out or receiving instructions
- 2Do not log in to any banking, email, or shopping accounts until the computer is clean
- 3Run a full scan with Windows Defender (Windows Security → Virus & Threat Protection → Full Scan)
- 4Download and run Malwarebytes Free from a clean device if possible — it catches threats Windows Defender sometimes misses
- 5Follow all prompts to quarantine or remove any threats found
- 6Restart the computer and run the scan again to confirm the infection is gone
Warning: If you receive a pop-up claiming your computer is infected and asking you to call a phone number, do not call it. This is almost always a tech support scam. Close the browser tab (or restart the computer if the pop-up won't close) and run your own scan instead.
When to Call a Professional
Some infections are too deeply embedded for consumer tools to remove completely. Call a professional if:
- Your antivirus finds threats but cannot remove them
- The computer is so slow or unstable that you cannot run a scan
- You suspect ransomware — your files have been encrypted or you see a ransom demand
- You believe your financial or personal accounts may have been compromised
- The infection keeps coming back after removal
Tip: If you have been hit by ransomware, do not pay the ransom. Payment does not guarantee your files will be returned, and it funds criminal activity. Call a professional immediately — some ransomware variants have free decryption tools available.
How to Protect Yourself Going Forward
Prevention is far easier than removal. These habits significantly reduce your risk of future infections.
- Keep Windows and all your software updated — most infections exploit known vulnerabilities that updates fix
- Never open email attachments from people you do not know
- Download software only from official websites or the Microsoft Store
- Use a strong, unique password for each online account
- Be skeptical of any pop-up or email that creates urgency or asks for personal information
- Back up your files regularly — a backup is your best protection against ransomware