Computer shuts off after a few minutes of use
My iMac (early 2009, 24") started shutting down after a few minutes of use. It's not a clean shut down. It's an instant cut-off of power.
Using Hardware Monitor, everything looks normal except with the Northbridge...
- The voltage sensor always shows 0 volts.
- The current shows 0 as well.
I've tried resetting NVRAM and SMC, but that hasn't helped.
Does anybody have any advise before I replace the system board?