|Do you know how to enter BIOS?|
With a Dell it is likely to be one of the following four key combinations while booting:
It would be worth seeing if they have messed with that or just Windows.
You could retrieve to valuable docs and pictures onto a flash drive using a Live Linux CD made on another computer. This is fine if your CD drive is already ahead of the HD but otherwise you need to get into BIOS to set it that way.
Always pop back and let us know the outcome - thanks