allowed a bit of malware to get itself installed on your computer.
You haven't mentioned what malware prevention you have been using but what you NEED is a GOOD anti-virus, and a couple of GOOD anti-malware apps.
I would recommend that you download the following and run them and I would further suggest that you do so in SAFE MODE.
3. Super Anti-Spyware
4. Dr. Web CureIt
RKILL is available at this link - http://www.bleepingcomputer.com/forums/topic308364.html - and that page also links you to the other three anti-malware apps. I strongly recommend that you READ the entire page so you don't get ecxcited about possible warnings when you run the utilities.
I have Windows 7 and cannot go to microsoft.com and some other sites because I get inundated with pop-up coupons. When I close one, another pops up and so forth as many as 8 times. I have a pop-up blocker that blocks, but these coupons somehow get through and they carry trojans. I use Microsoft Explorer.