Scanner Status Zero

I’m using Avast 4.8 Home
Build 4.8.1296
VPS file version 081220-0
Windows XP Pro
Comodo Firewall

When I running a scan with Avast the Current Scanner Status remains on 0%
Anyone know why that would be?
Thanks for any advice.

Can you be a bit more specific about the type of scan that stays at zero.

Is this a full scan of your hard drive(s) or a scan of a single file? If a single file what was the file type?

Thorough scan. Even after 40K+ files it still reads zero.

Well, maybe there simply are many more files to go?

No. That would probably be over half, maybe about three quarters of the files.