cannot update from 1.07 to 1,09

[uncus]

I had moved the game from a failing disk drive to the current drive [where the game plays fine.]
I just saw the 1946 DLC and purchased it.
When I try to update, the update only sees the path to the old drive.

Is there a registry key or config file that I can edit to point the installation/update to the correct drive:\folder?

I know I can uninstall and re-install, but that seems to be a lot of work [and potential loss of campaign units from the 39 dlc on] to do it that way.

Thanks for any suggestions in advance.