Despite the title, it’s important to note that if your computer is infected you may not have any indication of that infection. Much malware leaves no visible evidence of its presence. But, some does and below are a few of the things that should cause you to investigate further…
- Your browser takes you to odd places. If a bookmark that has been directing you to your favorite site suddenly starts to direct you to another site that maybe tries to sell you something then the bookmark might have been hijacked by malware. Similarly, if you type in a URL but get taken to a completely different site address that should raise your suspicions.
- You try to access your anti-virus software but can’t. A number of malware beasts will attempt to turn off your anti-malware protections (e.g., anti-virus software, adware detectors, etc.). Often they are successful and sometimes will even deactivate any shortcuts to the program(s). If you’ve tried to access your anti-malware software and can’t, that’s another reason your suspicions should be raised.
- You start seeing ads but your browser is not active. If ads start to pop-up on your system without any reason you should be very suspicious. Even worse, if these pop-ups say your computer is infected and attempt to sell you a solution, don’t wait. Immediately find out what sort of malware you have and get rid of it. That’s pretty much a dead giveaway malware is afoot.
- Your social media sites start showing posts from you that you didn’t write. Fake postings on social sites are a strong indication your computer is infected. Their purpose is to get your friends and followers to click on links in the post so that your friends and followers might become the next victim. Do them a favor and investigate your system for malware.
- Systems tools are unavailable. One of the ways to investigate what’s running on your system is to use the Task Manager and other related system tools to see what programs and processes are running. It’s not a foolproof method because many legitimate processes have really odd names. But, if you can’t open these tools at all via an administrator account then you should seriously look into the possibility your computer is infected.
- Friends start to call you about being stranded on your trip to [insert any far-away place]. One of the payloads in malware is to send E-mails to your address list and other mail addresses found on your system. A popular messages appears to be from you saying that you are stranded in some exotic place and you are asking them to send money to help you get back home. The instructions are to wire it to some location. The problem is you are not there and once you wire money from your bank account you can’t usually get it back. Calls like these from correspondents should be a clear sign you have an infection.
There are probably other subtle signals you could look for (e.g., system runs very slow, the internet connection or hard disk seems particularly busy for no apparent reason, etc.) but the ones above or indications similar to those are pretty common signs of an infection. Get some anti-virus software and check your system as soon as any of these show up. Better, have some running before the infection to help keep your system clean.