I have used norton for years,And it's never once been a resource hog for me!!!
Well I think I have solved this issue,
I went for a fresh install and as opposed to just clicking format on the vista CD I also clicked delete (I'm a tool) and it freed up the remaining space on the drive. I then installed and I have had no BSOD during vista loading bars, no mysterious disappearing icons. And vista is running nice and quick (for vista).
Only got basic installed for now but I'll put premium on tomorrow. All looking good.