I work at an internet cafe/LAN center that also does computer repairs and I just received a call from an irate customer.
Me "Hello, [Business name] how can I help you?"
Him "You guys broke my computer. I payed you to fix it and now I got a virus and lost my final project for college."
Me "Sir I can guarantee you that we did nothing to hurt your computer. If you'd like to bring it in I'd be happy to do a complimentary virus scan/removal."
Him "NO, I'm not gonna bring it in so you guys can get more money from me and not fix my computer."
I'm on the phone with this guy for about 10 minutes trying to find out what could've gone wrong with his machine and he finally admits to clicking on pop-up ads for something or other and that's when his computer went to hell.
Him "I THOUGHT YOU GUYS GAVE ME ANTIVIRUS SOFTWARE!"
Me "That is correct, we installed AVG FREE on your machine. But even the best antivirus software cannot protect you from viruses if you are clicking pop-up ads and saving suspicious files onto your harddrive."
Him "THAT COMPUTER HAD ALL MY COLLEGE WORK ON IT! IT'S YOUR FAULT IT'S ALL GONE NOW!"
Me "I'm sorry sir, but I was not the one clicking pop-up ads on your machine. Like I said, if you want to bring your machine back in I'd be happy to do a complimentary virus scan and removal."
Him "I'VE HAD IT WITH YOU GUYS. I'M JUST GOING TO GO GET DRUNK AND DO DRUGS"(no joke, thats what he said)
Me "Good luck with that sir. And I'm sorry we were unable to help you in the way you wanted."
honestly, no antivirus software can stop you from being an idiot with your machine.