I have replaced a power supply in a Compaq computer running Windows XP. The power supply had failed and the fan was not working. It would not boot. When I replaced it, it booted fine into the accounts that were already set up (naturally there is no password on the limited account). Unfortunately, since I cannot get into an administrator account because of the keyboard failure(cannot type the password), I cannot make any substantial system changes. When I use the keyboard, it simply does not respond (I tried three including a wireless) and the mouse freezes once I type anything into the keyboard. I do not see a keyboard listed in System Utilities. I do see a mouse (and in fact can use it for a time). On boot, there is a message relating a keyboard and mouse error but it goes by so fast, I am unable to read it. If I press the keyboard to get into setup, or safe mode, the screen says "setup" in the lower right corner, but the screen remains black and does not actually get into setup. It will not boot into safe mode. I put an XP disk in to try to repair or reinstall drivers if that is a problem but when the screen says "push any key to boot from CD", my keyboard does not work. The CD rom disks work, and the light appears on drive A, so I am thinking that I did not hook anything up wrong, but I could have?. Is this a motherboard problem or corrupted drivers or what else? I first need to bypass passwords using the mouse. Is this possible. Then maybe I can install drivers from drive A if they are selfexecutable. Any ideas? Help please if you can. Thank you.