BSODs, maybe Firefox or Flash

Microfrost · 18 Jun 2013

Britton30 said:

It would seem that your PSU is not putting out the correct volts when booted. It could still show OK on a volt meter, how did you check it? The reading should be with +/- 5%, not 10%.
Go to the hardware section of your BIOS and see what voltages it is reporting, I never have trusted Speed Fan.

The valid SpeedFan readings (left column) agree with the BIOS, though I forgot that for this PC, the power supply doesn't output -5V. However, I just re-checked the -12V rail with a volt meter between ground and the ATX power connector pin 14 (blue), and it is -12.21V, well within tolerance. 10% is the correct tolerance for the negative voltage rails only (source).

Britton30 · 19 Jun 2013

Note it says" little-used negative supply voltages". The positive volts are more important.
Did you check volts while running an intense game or video coding?