Well you could always try an online scanner which will look through your pc, and then tell you step by step how to delete the files.
These will both scan your PC. I'm not sure if the first one has the ability to delete files, though I know the second one just tells you how after finding them, though its not hard
Plus, after this is fixed, get yourself a good antivirus program, like Norton or a free alternative, AVG Antivirus which is great! Plus if oyu haven't got spyware detectors then, get a free one of those, and same for firewall if you hvaen't got one, and a good free one that I use is, Zone Alarm
After this is sorted out, we'll give you links to these programs if you want to protect your pc, as they are very important to have.
I hope this helps