So how do you know when you’ve been infected, anyways? Well, that’s the funny part. Unless you have a big message on the screen saying you have 80 viruses on your machine, you’ll probably never know. Most people don’t until they look for it.
Some of the easier ways to tell if you’re infected are the somewhat obvious ones. Your computer gets slow or sluggish. You have errors when you load up your computer. You have friends messaging you telling you to stop sending them your darn IQ score. You get a random email from a person in your address book asking you what in the world web site you sent them. These all can mean that your computer has been infected. The only definite ones are the hijacked IM and email boxes. The other ones could be other computer issues.
Some of the other telltale signs of a virus on your machine might not be signs on the computer at all, but rather those from the real world. Phone calls from creditors or companies calling to confirm a recent purchase. Phone bills showing 1-900-SEX-LINE being called 40 times a day. Letters from companies you’ve never heard of or signed up for. These may all be legitimate (though I would worry about you if the 900-number was you…) but sometimes they could be indicative of a virus being on your machine, stealing your information and compromising your security.
Oh, of course you’re also infected if you have a huge thing on your screen saying “YOU’RE INFECTED!”