I was getting the fatal system error of C000021a during shutdown.Nothing bad occur during the startup so i can still use the computer.
When the fatal system error occur,i simply unplug the power supply and plug it in again.
Then i start the computer as before.
So there isn't really much problem except that its irritating to unplug and plug.
I tried restore point and the error will pop up during restarting...
I was afraid that the unpluging and plugging will slowly destroy my computer...

Ypu might want to look at This

A further Microsoft link that may assist you.

kind regards,

I asked one of those experts and they said it could be harddrive error.
I let it ran the error-checking but there are no errors!.
Also,i used less then 1/10 of the hard drive.

Could it be software error?
Could running xp repair install be a solution?

Have you got backup for this system, although a repair install should not loose your programs installed.

If you want more assistance for this please ask.

kind regards,