|did you try turning off system restore and then scanning?|
If you did, you may have a rootkit installed on your PC.
You may want to try unhackme, follow the beginners guide on the left of the install page. Run all the scans untill the PC is clean.
There are many options in the program, be sure to use all of them especially when you don't know if you want to delete a questionable file.
Try googling the file and see if it is safe to delete.
Once the PC has no more infections you can uninstall unhackme.
Some HELP in posting on Computing.net plus free progs and instructions Cheers