I had sh!tloads of problems with this, but go into safe mode and once you scan with Spybot and find the locations of the pieces, usually a couple in the registry and a couple in the windows folder, you can delete them without them refusing you access. You can use the automatic fix on spybot or your other virus software, but given the trouble of getting rid of them before, I decided to manually go into the windows folders and regedit so i could SEE them gone. After that my system was just fine.
So yeah, safe mode will allow you to delete them finally with no refusals.