Incorrect Scan History

MSAS SCAN HISTORY INCORRECT

System Summary says total scans 20, the last being on May
11 2005. Scans have been executed on a regular basis
since then but are not recorded. After each subsequent
scan the number of scans increases to 21, but reverts to
20 on the next boot. The delete this spyware scan history
button left the history intact.

Spyware Definitions are dated May 9 2005, even though
there have been updates since then.

No scheduled scans are recorded even though the computer
is connected to the internet at the scheduled time.

Please help. It will be appreciated.