Hi,
Try looking in the BIOS.
When you boot up, keep your finger on the 'delete' key.
Once in the BIOS, be werry werry careful. [If you make a mistake, just make sure you DONT save the settings]
If you are not sure about finding your way around in the BIOS, get a mate to do it, cos you can badly screw the poota to the point where you can't get back into the BIOS without clearing it.
Good luck,