I found Xupiter in my registry, and it only took the deleting of the value to get it out (two lines actually). It's in the Run section, but more specifically: HKEY_LOCAL_MACHINE>Software>Microsoft>Windows> Current Version>Run.

I hope I helped, I know those kind's of programs can be annoying to get rid of. I have Ad-Aware, and it does help, but quickly removing the registry keys helped a deal.

Disclaimer: Only edit the registry if you've done it before or anything, don't tamper with it a great deal. Tampering with it can mess up the system, so unless you've used regedit before, don't go into the registry files.