XPS 410, black screen with flashing cursor?

I am trying to help out a friend who somehow managed to really cause quite a lot of grief for himself with his Dell XPS 410.  From what I understand he somehow locked himself out of being able to make any changes in Set-up, etc. because he forgot his password.  He did not know about the password reset jumper on the motherboard, so tried some other methods, that ultimately led to it's current status as mentioned in the title of the post.  He also tried to boot from a usb device because somehow something changed or went haywire so he could not get to windows.  I know it sounds like he has bricked the mobo, but if he has a flashing cursor is not that a sign of a bit of hope yet?  Before I buy another mobo, and have to transplant the processor, etc. is there anything else that could possible be done to get this computer back to windows?  I will be picking up the computer this weekend, but wanted to get some more advice before spending the money on a new board.  My guess is that perhaps the computer is still trying to boot from the usb device, or external HD.   Thank you in advance for any help/advice you might have.  Also, if I do need to just get a new mobo, do I need to worry about the password issue?  Have never replaced a mobo before.