Why do i have to log off twice to effect a logoff?

Archived from groups: microsoft.public.windowsxp.basics (More info?)

Any clues please?
Windows XP and while the pc and software appear all to be operating ok
when i go to log off the hard disk rattles a bit and it looks like it
might log off , no other indication and yet when i select the log off
a second time away we go and it logs off all ok.

two users and sp2 installed and updated. nearly identical other pc
with same AV and software seems to log off 100%.

Any suggestions would be appreciated.

Min.