Did you interrupt the operation of placing the files in quarantine in any
way?
If the quarantine completed properly, the only suggestion I have is to leave
the program sitting in the quarantine UI for a good long while, to see
whether the files will appear in the UI to be un-quarantined.
I don't have a good feel for what to look for--I'd think that task manager
should show some Microsoft Antispyware related process using significant CPU
during this process. If you don't see that, I think that's bad news.
These file may be basically renamed--so if they are MP3's, for example, a
utility capable of renaming the files according to title information in the
files may do the job for you.