Welcome to Opera's forums @Oakpaul!

Program files x86 or Program files depends on the Opera version, x86 (32 bits) or x64 (64 bits).

Did the new install restored your previous data?
If You need to recover your bookmarks or any other needed data, check the profile folder in %AppData%/Roaming.

Check in the new install:
OMenu > Help > Find Solutions

Once you checked that (if needed), you can try with iObit uninstaller and cCleaner to uninstall and clean any traces of the broken installation.
(There are portable versions for both programs too)