Hi There guys, bumping this back up with some results.
I have installed and run CCleaner, seems a very handy tool, managed to free up 2gig of extra space, lovely! However running that Procexp caused some problems, just running the program listing all processes, before i could make much sense of it all the system locked up badly and then went BSOD on me.
Does that help diagnose at all?
I've still not had a decent chance to run memtest yet.