SP1 Problems

Can anyone explain, is there a subtle difference between CTD, and the screen going black and the computer rebooting, only my PC does the rebooting scenario now I've installed SP1. I've read most messages on the subject, and I followed advice from AltimateOne posted 13/06/07 who got a complicated in-depth email reply from microsoft, involving msconfig and regedit/defrag. I believed this had fixed my problem because I had been flying on and off the past few days totalling approx 7 hours, but today I flew for 35 minutes and then the computer rebooted. I was not changing views at the time it rebooted. Many people give reference to the file msvcr80.dll but I am now not getting any error message let alone reference to a file. When my pc first rebooted I got a message saying a fatal error had occurred and would I report it to Microsoft. I tried to do this but I got a message saying the file was corrupt and it could not be sent. My patience is running out, I think I will remove SP1 for now unless anyone can help me. My system is AMD6000+ dual processor, 2GB ram, Nvidia 7900GT with latest 94.24 driver all running on Windows XP. I would be grateful for any help.