Hi, thanks for the quick replies guys, much appreciated, I didn't want to post a response without some kind of progress to report on my part.
After 5 frustrating days I have finally made a breakthrough! I took your ideas on board and initially thought it was something to do with my graphics card driver, then I nearly broke my PC altogether after messing with the file ntoskrnl.exe!
The last couple of crashes though gave mention to the file symefa.sys. After a bit of googling I discovered that someone on the symantec forums was having similar trouble to me. Turns out Norton trying to initialise background tasks was causing the blue screen. Someone suggested turning on silent mode in Norton, which would prevent this. I have and have had no crashes for over an hour now (was crashing after 5 mins tops before).
Hoping an update from Norton will now fix this altogether. Sorry if I've kinda wasted u guys time, but it did start happening straight after the quake update!
Many thanks again
