I accidentally installed ubuntu on the windows backup partition of my computer. How can I uninstall it with out messing up the windows backup?
I would not worry so much about your backup partition. In windows booting from a repair disk/install disk has the same effects as booting from your backup partition.
Also if you did a normal installation of ubuntu then I would say the partition already is unrecoverable. Ubuntu usually, when given the permission to install the partition, erases the entire partition and rewrites Ubuntu files to it. I'm sorry if you really wanted the recovery partition.
Here is how to recreate one though!