"Weird events" can be caused by system instability as well. I learned my lesson with my AMD Opteron... it wasn't fully stable, and my Windows installations all eventually got screwy like yours (both XP and Vista [I had both installed in a dual-boot configuration, using 32-bit]).

Keep this in mind: neither IntelBurnTest nor Intel(R) LINPACK sets anything to start on Windows startup, nor start stress testing without the user's consent.