My laptop will not load Windows XP. When Windows XP tries to load, it says that a system file is corrupted or missing...which I suspect is a virus. It then says to restart and put in the Setup disc and press r for repairs, and then the laptop restarts whenever you press any button. My problem is that the DVD drive on my laptop is dead so there is no way I can do this. I have a external usb cd-drive but I do not know how to configure my bios to load the usb drive without first loading windows, because it is not listed in the boot selection list. Any Ideas??