HELP! Hack prevention for ADMIN account. (WXP-Pro)

[littlejoestorm]

hi, is there a way of preventing a "limited" account from trying to hack in to an administrator account. My sister has an xchange student staying with her and he's been trying to access the administrator enabled accounts. He's been searching the internet for ways. Can i prevent him from using some sort of boot disk to disable him?? Please help!

[motoflop]

Check computer bios settings. Set boot sequence so that diskette boot, usb boot and cd boot are either disabled or logically after harddisk boot. Then set bios password to prevent changes for bios settings. Now it should not be possible to use other boot media to bypass normal boot.

[cyclic]

Could you not just tell him to act in a reasonable guest in the house or evict him, he is really attempting theft, you should not have to change your personal property to stop someone misusing it, tell him straight, 'shape up or ship out'
I know what my solution would be but I cannot allow myself to post it publically.