Hi guys,
My friend brought over his pc (an ECS K7SEM with 1.1ghz Athlon and 256ram running xp). Everything has worked fine since being built over 2 years ago.

A few days ago he started running into major trouble. The computer continually runs into bad_pool_caller or other BSOD's, although many times it just reboots itself before even getting past the XP loading screen. It will do the same in safe mode.

Now, i have tried everything: testing ram, power supply, video card, cables, hard drive..... i even tried putting a different hard drive and trying to install windows xp... and it reboots or freezes at the first screen where you can do repair, new install etc.

Then i decided to upgrade BIOS.... no help.

Now here's the strange part.... i disabled the L1 cpu cache and it will boot normally into windows and will navigate and stay on as long as i've allowed it (although slow as molasses in january is an understatement....totally not useable in this state). However, does this mean that the processor or it's L1 cache could be faulty?

*I should mention that when i did boot up with L1 cache off, it came up with a LSA shell (export version) error, and later that it recovered from a serious error on nov 2/04........ the same time he started having trouble. He has SP2 and had been up to date with updates and virus definitions.

Any info is appreciated..... this one is proving to be a tough one for me.

It is possible you have a bad CPU. I would suggest getting another socket A cpu of any time just to test with, if you can.

You could also have heat or power issues. Turning the L1 cache off will starve the CPU so it will work only at a fraction of its capacity.

I looked in the BIOS and heat was less than 50celcius for cpu core, and there is plenty of airflow in the case. I did try a new Enermax 350w power supply and got the exact same restart/immediate freezing.

However, i did notice that the current 300watt power supply is kicking out around 13.1 volts under the +12v.......... it emits around 12.4v when using the new Enermax psu.

So:
a)Is 13 volts too high?
b)If so, could the power supply be slightly faulty and the 13volts could have caused cpu damage?

13.1 barely fits into 10% standard tolerance so it probably is bad. On the other hand only drives, fans and truely ancient peripherals actually use the 12V power supply.