what you're describing sounds like "scare"-ware. it's all over the net and tends to trick you into thinking your system is infected with viruses via pop-ups and ads. "personal av" or "personal antivirus" is a very common one that fools alot of surfers.
if you fall for the scare tactics and get infected then you should go to download.com and install "malwarebytes anti-malware". it's free and you would just need to update the engine and run a full scan afterwards. whatever antivirus software you use should be manually updated also. i always turn off the system restore feature, and boot the infected system into "safe mode" and run full scans using my anti-virus program and malwarebytes anti-malware.
gets rid of everything everytime
these are instructions for pc's, but mac's pretty much work the same way. and before some nitwit says "mac's don't get viruses"........ask the wizard of oz for a brain so you won't be so gullible!
