possible rootkit

I have here a machine i was cleaning up of viruses and spyware. got it running good. was doing a defrag and it stopped because it couldn't move a directory in program files named Micilla! I can see it using knoppix but can't remove it i tried using mepis but still it wouldn't delete. I checked it with rootkit revealer before using knoppix or mepis and it showed up as a rootkit. aside from formatting how would i get in and delete this directory. the OS is wp home formatted ntfs.

Never had to deal with one of those nasties myself,but a very good place to look for help would be here ...