[OT] flaky power supply?

[Andrew Gould]

Hi All,

When I booted up my sister's computer, I heard an occasional click.
It reminds me of circuit breaker tripping, but not as loud.  When it
occurred while Windows is booting, the "busy" light that goes back and
forth paused, then continued, but the computer didn't finish booting.
When it occurred after boot up was complete, the computer would pause,
then everything would go flaky (Windows Explorer would fail, for
example.)

The computer no longer successfully boots up as a config file is now "missing".

Is this most likely a power supply problem?  Could it be a hard drive
or motherboard problem?

Thanks,

Andrew