I am not sure, but I think that Rtvscan.exe belongs to Norton. Norton can be a real pain, so you may have to uninstall Norton, and reinstall it, as there could be a corrupted file.

Also, if you removed Norton recently, perhaps Rtvscan.exe is a remenent, of Norton, looking for a place to go, in which case you may need to do more uninstallling and go to Norton's site to look for a removal program.

This computer is probably a school's computer, so they probably have Norton on all their computers, but if this were your personal computer, I would say get rid of Norton (resouce hog), and download a free antivirus program (AVG, Avast).

It could also be a virus that is playing games with Norton...lol.

I would also run some usual Malware programs, Spybot & AdAware.