How remove the spyware

I am facing a common problem in many PC i.e When I try to open a Drive in Windows XP Explorer the folders inside the drive is automatically hidden, more over the “Folder Option” in the Tool menu in Explorer is not showing. I tried with many Virus removal software and other anti spyware software but the problem is still there. I deleted the Primary Partion and newly created it and formatted the following drive and moreover reinstalled the O/S but the problem is still there………
Please Give me a permanent solution for the proble as i am a rugged(confisued) state and my customers are in a very problem……….