Hi dave,
Try this fix from Bill Sanderson:
1) Uninstall Microsoft Antispyware
2) delete the \program files\Microsoft Antispyware folder and all
subfolders. You will lose access to any Quarantined items, history, and
customized settings.
3) Reinstall Microsoft Antispyware, being sure to be logged on as the
administrator user who will customarily use the program.
The key here is step 2--one or more of the .gcd files that direct the
programs
behavior is either corrupted, or has permissions set so that it isn't usable.
I hope this post is helpful, let us know how it works ºut.