Hi :
I hope it's not the case but there are severa;l virus and even trojans
which can infect the winlogon process thereby gaining entrance to your
system and potentially all kinds of nastiness. Because winlogon drives
many other processes it is quite a target. Also every time you logon
you would be re infecting. If you have not done so I would run your
antivirus, and firewall programs, Spybot, Ewido and maybe Trojan Hunter
to see if they can find anything. Best done in Safemode and with System
Restore switched off. I would also delete the contents of the Prefetch
directory in Windows before starting that.
If you are a little more adventurous try running Process Explorer to
see what processes are linked with winlogon.exe when it is running. IIf
any are unknown or suspicious you have a start... PE can be downloaded
from
http://www.sysinternals.com/
Good luck
Tanimoto