problems with keyboard, blocking pc

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Hi,
recently I bought and builded a pc with Asus A7V8XX motherboard, Sempron
2400+ processor, Maxtor HDD, and 512 MB mem.
I installed XP pro with sp 2, and sometimes, after startup, the system
blocks after U give input with the keyboard, like an adress, or something.
Does anyone have a clue to this problem. I already checked the Bios, and
it's version 1013, so OK for Sempron.