It worked for a while, now the problem is back worse than ever.
I have up-to-date drivers for the mouse - it's a Labtec optical mouse, and up-to-date Hyperion Drivers for the Via chipset.
I don't know whether this is any help, but here goes, I was playing the original Dungeon Seige or Return To Castle Wolfenstein when it showed up, it either sticks or the ground seems to dissapear and a sign appears ''Gathering Exception Data - This could take a few minutes'', at this point the game stops. I have also loaded the latest catalyst drivers for my ATI card.
Although it originally showed up in the games mentioned above, it also occurs with increasing frequency when I'm using other programmes, such as MS Office XP Excel and MS Office XP Word, it also appears when I use either of my two e-mail clients, MS Office XP Outlook or even XP's Outlook Express.
All my system specs and some other data is already on my profile.