its the download that did you in
if you had anything important on it you might want to take it and put it on a flash, or just back up what you need, and do a re-install
although look into it a little more, and be careful with what you downlaod
don't jump onto a re-install until your 100% sure theres nothing else you can do, cause theres no system restore on that
HAVE YOU TRIED A SYSTEM RESTORE?
go start>help and support> then on the left it says system restore, try that and it should undo everything that was done back to a certain point