Recently i was facing a problem of the imilar type with norton antivirus and in the quarantine folder.
So, according to what i observed, the quarantined file was still infected and was also increasing its size. It had increased to a size of 580 MB. And my CPU was busy to 98%.
Luckily as I was using two Windows XP on two different HDDs, i booted into the other os and deleted the files in quarantine folder. Now my system is working file. My comp was infected by win32.pif virus.
So, u can try deleting the files from the repair folder where it hangs. In my case NAV use to hang at two places, the first being c:\program files\norton systemworks\norton antivirus\quarantine and second in my games folder where i had installed Wolf ET.
Can't guarantee this will work. But u can give it a try