Hi - any help here will be very much appreciated. I installed SP2 last week and since then my system has frozen every time about 16 minutes after booting up / rebooting.

The application I'm using at the time continues to function after 16 minutes but everything else is dead (i.e. no response from taskbar quick starts; no response from desktop program icons or from the "programs" menu.

I've tried monitoring my resource usage to see if something is stealing memory or whatever but can't find anything. CPU usage is running constant at around 45-50% (mainly due to Spybot Tea-Timer).

Thanks in advance!

Tea timer is known to have few bugs ,you could try disabling it and see what happens.
Any program that is using 40-50% of your resources just to run in the background wouldn't be running on my computer !

Caperjack - many thanks. I disabled Tea-Timer from within Spybot, rebooted and noticed a significant improvement in general system performance (CPU usage was also down from 45 - 50% to 0 - 3%).

More important, after the dreaded 16 minute wait everything kept on working! I'm now at zero + 50 minutes and everything's humming along perfectly.

Problem fixed. Thanks for the advice.