No luck I'm afraid.
I probably should have been more detailed with my initial post, so hopefully this little bit extra might help. Sometimes the PC will crash mid boot and when I can log in it will give me the BSOD at least once before running smoothly (providing that it's not shut down). In the last couple of days it's taken to freezing when booting and it can take between 5-10 mins before it runs without BSOD interruption.
Also, I think it must have been in a strangley good mood last night, because it BSODed me when booting to safe mode this morning.
Any further help will be very appreciated.