I don't know what you have. But see if you have a system restore on yours. Go to accessories then system tool and see if you have system restore. Set it to go back to a date when you know your computer was running right. You will/might lose some things that have been added sense that date but it's worth it if it helps.

Now if you have a older system like 95 98 you wont have a system restore. In that case you might just have to do a quick restore with your original CD that came with your system. Anything you have download save the links before you do it so you can go back and re-download. Save everything else on CD if you can. It's a pain, I know.

Then get the anitvirus....it's so important to have and I really believe you have a virus. It's a must have!

it scans....finds the bad folders/files...but it won't quarantine/delete them.
As for the Ad-Ware not deleting or quarantine files, you did check them to be deleted, right? I only ask because a friend of mine said the same thing once. She didn't know it was up to her to tell the ad-ware what do do with the files. She just thought that once it found the files it deleted them automatic, like her virus control does.

Also have you ever gone to windows update and checked for any new software up-dates that you might need for your system? Sometimes you need to up-date new sercurity systems, etc.

Just trying to think of all the things that could help you.

All in all though I'd say you have a virus and you really need to check for that.