Hi Paul have you tried starting up in safe mode if you can and running scandisk/virus checker etc
The usual way to get into safe mode is to keep pressing the F8 key at bootup. This leads you to a list from which you select safe mode.
If pressing F8 doesnt work, reboot and this time hold down the control key. If neither work have you a compaq manual? This may show how to get into safe mode.
Also when the laptop froze last night did you get any error messages? What was the laptop doing when it froze?