Norton won't scan and won't scan much in safe mode

I'm currently working on my godmom's laptop which I believe has the Trojan.Fakeavalert!Gen virus. However when I attempt to run a scan in normal mode my scan window will pop up and say it's scanning, but the file indicator will stay on 0. I've attempted to run it numerous times after numerous restarts with no luck. When I run the scan in safe mode, it comes back and tells me it's finished scanning after only scanning some 3700 files, and I know this computer has well over 150k files on it. I suspect it has the afformentioned virus because the auto-protect popped up with a window saying something about an alert for that infection. However it doesn't give me any other information and it doesn't show me what files are infected so I can remove them. What can I do to get Norton to actually run a full scan in safe mode instead of the partial scan it's doing?

 

The computer is running Norton Internet Security 2008 and has Window's Vista installed. 

 

Thank you.