Random crashes without BSOD

there we go

Just go two crashes almost in a row.
2 new critical error reports on event log:

Log Name: System
Source: Microsoft-Windows-Kernel-Power
Date: 26-08-2010 00:38:20
Event ID: 41
Task Category: (63)
Level: Critical
Keywords: (2)
User: SYSTEM
Computer: superjoao-PC
Description:
The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />
<EventID>41</EventID>
<Version>2</Version>
<Level>1</Level>
<Task>63</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000002</Keywords>
<TimeCreated SystemTime="2010-08-25T23:38:20.844416400Z" />
<EventRecordID>2067</EventRecordID>
<Correlation />
<Execution ProcessID="4" ThreadID="8" />
<Channel>System</Channel>
<Computer>superjoao-PC</Computer>
<Security UserID="S-1-5-18" />
</System>
<EventData>
<Data Name="BugcheckCode">0</Data>
<Data Name="BugcheckParameter1">0x0</Data>
<Data Name="BugcheckParameter2">0x0</Data>
<Data Name="BugcheckParameter3">0x0</Data>
<Data Name="BugcheckParameter4">0x0</Data>
<Data Name="SleepInProgress">false</Data>
<Data Name="PowerButtonTimestamp">0</Data>
</EventData>
</Event>

(both are the same)

Done all that, im running prime95 for 30min already , no crashes or anything like that.
Going to do a gpu stress test now.

system crashed at around 10seconds of a Furmark stress test, just a stability test at default settings with gpu temperature enabled, at the time of the crash the gpu was at 69º .

im back again, its not an overheating issue for sure, it just crashed while i was browsing with the gpu at 43º.
Also, after being stuck and not being able to load windows for like 5 tries in a row i decided to increase the cpu voltages and overclock it a little bit, funny that i manage to load windows, and to run Furmark without any problems, yesterday it was crashing, now it runs it fine, im not that much ''into'' this, so i was wondering if it is possible that a voltage increase on the cpu could make the 12v more stable or something? is it possible that the 12v isn't feeding the gpu as it should and making it the reason for the crashes? increasing the gpu vcore values could make it more stable?
Also, is it possible that a psu that is 2weeks old decided to go unstable by no reason?
I can only see 2 possible problems atm, either the gtx 480, or the psu. Unfortunately i dont have the chance to switch either of those to do some tests ;\ .
(note that i did run a memtest for around 6 hours and it was error free, i also did a prime95 test on the cpu, everything related to the cpu overclock is ok, including temps and so on)
Thanks in advance once again.