N1000c power cycles when USB device is connected

PC SPecs.
Compaq N1000c with 512 Meg Ram.
All other features as standard.
OS: XP SP2 + all OS updates.

Problem:
When i connect any of 4 different brand/size USB keys the laptop power cycles without warning.

These keys work fine on other laptops and PC’s.

Have completely re-installed OS from scratch, to no avail (didn’t think to test before applying MS Updates).

Any Suggestions (other than get a newer laptop)?

Thanks,
Ed.