If it's not sensor malfunction, then your motherboard really is garbage. As videocards use both 5 V and 12 V (and pretty much all kinds of voltages really), it might have caused the card failure too.
Ah, but video cards don't take power from the +5VSB line. The only thing running from this line is the power & reset buttons on the case as well as (in the case of an IP35 Pro, which I have) the LEDs on the mobo indicating proper power connections. If the primary ATX +5V rail is in spec, peripherals running from same are in no danger.
To the OP: No idea why it's out of spec, but since its only function is to provide power to the power switch, or to keyboards & mice if you have them defined as "wake-on" devices in the BIOS, I'd change the alarm range in uGuru as long as the voltage isn't rising to crazy levels (anything much over 6.5v).
Another possibility, especially with the IP35 Pro, is that the heat tube that covers the PWM circuits around the CPU socket may not be making proper contact with all of the associated heat sinks. Lots of reading here:http://www.xtremesystems.org/forums/sho ... p?t=147163
Build a man a fire and he's warm for the night. Set a man on fire and he's warm for the rest of his life.