I think that it could rather help if you'd disable the automatic boot/restart windows feature, as then you'd be able to read what error exactly does the blue screen shout about.
Such critical errors in Windows can happen (or start happening) out of a sudden and be caused by anything, mostly though by some minor software-software, software-hardware or hardware-hardware incompatibility... I had a really unnoying autumn last year, when my WinXP suddenly started bombarding me with "IRQ_NOT_LESS_OR_EQUAL" blue screen messages in the middle of everything I was doing. A search finally discovered the culprits being my Asus Mainboard (working its chipset off out there for over a year), GF FX5900XT Graphic card (whom I had for about half a year), my ADSL modem (likewise) and... the "Dawn of War" game, which somehow made a conflict between all those hardware components (which never before caused even one problem). All the time I was running one and the same clean copy of Windows XP PRO SP1, with all the updates (except for SP2 of course) and yet never before did it froze even once...
Anyway, if you manage to pinpoint the error message that your Windows is shouting at you, it should be much easier to find a solution. Even a simple Google search for it should reveal several forums with people, who either experience or were experiencing similar problems...
Heh, it suddenly got to me that it looks like I'm inviting you to an AA meeting
