It sounds like you are pretty computer literate, so.

I'm going to suggest that you download a program called hijackthis.  It's free and it will tell you what is running on your computer.

Get it at http://www.pcworld.com/downloads/file/fid,23258-order,1-page,1/description.html

A safe site to download form.

When you run it it will offer to do a system scan and save a log file.  Copy the ENTIRE log by pressing Ctrl + A  then press Ctrl +C to copy it into memory.

Now go to http://hjt.iamnotageek.com/  and paste your log into the big blank area that is the log analyzer.  To paste it press Ctrl + V.

Now click on the the box at the bottom that says Parse.

It will show all the programs and files running in different colors.  If you have things in RED they are possible problems.  Run hijackthis and in the box next to files you don't want running put a check mark.  Then click the box, Fix This.  It will remove the program.

Or take it out of the startup group.  Sometimes it's necessary to turn off system restore because programs hide in there and when you reboot they come right back.  For the same reason I empty my prefetch folder and my recycle bin.

Any program you find that is marked RED should be checked using Google to discover what it is and what it does.  Don't trust the first link though as some places want to remove every dll or exe file and say you need to download their program.

Read through and find out what the consensus is regarding anything you find.