Help a file that keeps rewriting itself

I have been cleaning a computer with the usual garbage ware installed. I have been able to remove the vast majority of the garbage ware. I am having trouble with a file called Tunb.exe. Everytime I delete the file and the registry entry and reboot the computer, the file gets re-written. It was hiding in a folder Program files\aole now it has switched to Windows\system folder. I have ran the usual software tools to remove this but it keeps coming back. I can post a Hijack This log if anybody is interested. It is a Dell computer running Win 98. If anybody needs more info let me know and I'll post it.

Thanks