Hardware

If you've got an XP CD, boot from it and when given the option, access the recovery console by pushing 'R'.
When it's loaded, type CHKDSK /r and see if it fixes any errors. When you've finished, re-boot your PC and then turn off the automatic updates.
You can attempt to update your drivers by going to the Control Panel>System>Hardware>Device Manager. Double click on your hardware devices and update your drivers ( you'll need to be connected to the internet ). Just try your keyboard\mouse and monitor for example.

Go to microsoft and download service pack 2 and install it, see how it runs and let me know if it still locks up.

Regards

Martin