Sometimes the attack is more obvious. If a program you don't recognize suddenly pops up and starts displaying dire warnings and asks you to run an executable file or asks for your credit card number, your PC is definitely infected with some nasty malware. Never fork over your credit card information or other personal data to a program or website that tries to warn you that your PC is about to die. More often than not it's a rogue program, fear-mongering malware that tries to scare you into giving up your private info by issuing doomsday warnings of imminent hard drive failure, catastrophic viral infection, or worse.
3. Check online for possible fixes
The one benefit of those scary pop-ups is that they could point you toward a cure. Use your favorite search engine to look for phrases that appear in the pop-up—you'll probably find other people fighting the same infection. Their experiences could help you identify your enemy or even find step-by-step instructions for removing the malware. Be prudent: Take advice only from sites that seem reputable, and remember to perform a full scan of your PC after you've followed any instructions, even ours.
Barring any clues that lead you to a magic solution, scanning becomes your next and most important step.
4. Assume that your old virus scanner is compromised
Don't waste time scanning your hard drive(s) with your regular antivirus program. After all, that program probably failed to catch the malware in the first place.
But don't be too hard on it. Nothing's perfect, and even the best antivirus program can occasionally miss a new or particularly cleverly designed virus. And once that virus slips through, your antivirus program is compromised. You have to assume that the malware, not the security software, is in control.
You need a fresh malware scanner—one that's not already installed on your computer. It must be capable of detecting and removing malware from your PC, and you need to run it in an environment where the malware can't load first. Linux is your best bet, but before you jump to that option, try booting into Windows Safe Mode to see if you can outflank your virus infestation there.
5. Use a lightweight scanner inside Safe Mode
Windows has a Safe Mode that boots a minimal version of the operating system, with generic drivers and nothing else. It doesn't load most startup applications and—most likely—it won't load the malware that's infesting your PC.
To enter Safe Mode, boot your computer and press the F8 function key before Windows starts loading. The timing is tricky, so it's best to mash F8 repeatedly from the moment the motherboard manufacturer's logo appears onscreen until you get the boot menu.
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