Are you able to run your Anti Virus in Safe mode?
Has this always been the case or is this something new?
Do you get any error messages?
Post a hijackthis log please. Download and then extract Hijackthis.exe to a new folder. Do not run it from the zip the desktop or a temp folder.
Here's a link:
http://www.merijn.org/files/hijackthis.zipDo not remove anything using HijackThis. Save the log and then copy and paste the contents into your next reply here in this same topic. It lists many types of entries. Some are good, and others need to be removed. We will help you sort it out.