Yeah, it did give me a choice when I installed it, but since I don't know anything about computers I just picked one randomly. This is actually the first time I've had any problems with it.
Unforunately, I don't think there's any path without a full reinstall. Even an in-place upgrade to 10 would stick you in 32 bits as far as I know.
Well, that's really not the problem now though. I found an earlier version for 32 and downloaded that and it opens fine, but there is a dll file missing, to install that file you have to go to the place where the program is and find a exe file, start it and install that. I did that and something called Microsoft C++ started installing, but when it was almost finished I git "unspecified error" and there is nothing further I can do now, so, fuck computers.