Just re-install it, for petes sake.
Reinstall is always the recommended method, if that is possible.
I have done that with a laptop and from that experience I found that it is very much easier if you can clone from the old drive to the new drive. When I reinstalled to a laptop before that machine wouldn't do anything. It wouldn't connect to a network, wifi didn't work, touchpad didn't work, even the NIC didn't work. I had to search and download drivers, put them on a flash drive, and transfer them that way. Then once I could get the NIC to work I could connect the machine to the internet and the search for drivers went a little bit easier. I just cloned another laptop this past weekend and it went very much faster than that reinstall process.
My wife has a laptop that came with software such as MS Office installed, and we don't have any media for reinstalling that software, so if I was going to upgrade her laptop I would have to clone it, or pay for the software again.