Back up your data.
Remove Origin and all associated files on your Origin folder. Basically a clean removal of ALL Origin files. Then reinstall Origin, maybe download a new client.
After installation (of Origin), download about 10MB of each game (this is ... Assuming you've got more than one game in Origin).
Then copy over your back up files to their respective folders, and 1 by 1, continue the downloading of those games.
It should automatically read files and install them.
I did this once with Far Cry 2 last year, when I still had the game (it's missing now, though)...
Anyway ... That method worked for me.





