[techtalk] What can cause a computer to turn off on its own?

[jennyw]

Here's an interesting hardware question. My computer has this habit of
turning on by itself and turning off by itself, and I'm not sure why. I'm
using an Antec case, and thought there might be problems with the power
supply.  Then again, it could be the motherboard ...

Another interesting thing is that the power problems began when I installed
my ill-fated Seagate STD224000N-SB tape drive (SCSI DDS-3, 12/24 GB). The
first time I removed it completely, things went back to normal for a while.
Then I tried to install it again and the weird power thing is happening
again, even after I removed the drive yesterday.

Any ideas on how to tell where the problem is?  Or do I have a weird ghost
in the machine that needs to be excorcised?

I think my strategy for now will be to buy a power supply and hook up
everything to that and see what happens.  This is sooo weird.

Thanks!

Jen