karmic upgrade gone bad

Ok I tried up grading last night my computer mouse froze and so I decided to down grade with a disk I had at the house. The downgrade worked, kind of my, mouse works but know I cannot log in. I tried the recovery password protocol and I get the following message: unknown user.

Is there anyone to recovery the password

if not

How do I get a fresh or clean down load of Ubuntu

Any suggestions on how to fix it or get the system to work ,even if I have to lose everything that is on the computer?

lose

If you are prepared to loose everything make a ubuntu cd and reinstall.
Can not guarantee mouse will work then though. However try a different mouse USB or ordinary PS/2 one. (Sometimes USB mouse works if you unplug and replug)

thanks

I should have said the touch pad will not work.

I used Heron to up load and I think I am dual booting bucasue it list other operatins systems as 9.10.

Thanks for the help.

I had forgot how hard it was to get the drivers to work with heron. On to the new problem driver for wifi connection.