Are you speaking of Active Desktop? If so, see line 402:
http://www.kellys-korner-xp.com/xp_tweaks.htm
--
All the Best,
Kelly (MS-MVP/DTS&XP)
Taskbar Repair Tool Plus!
http://www.kellys-korner-xp.com/taskbarplus!.htm
SupportSpace
www.supportspace.com/pages?aiu=kellyskorner
"Arran" <(E-Mail Removed)> wrote in message
news:5CE2B0FF-590E-4483-95BA-(E-Mail Removed)...
> Can anyone help me? Now and again after logging on the active screen
> deactivates after about 30 seconds, click the screen it is reactivated but
> then deactivates again, This will carry on indefinably until I either
> reboot
> or; as I found out by accident that if I went to System Restore but just
> clicked the cancel button the active screen would then behave normally.
> This
> has been a periodical problem for months. I have XP with sp3.