Help, I desperately need my Lightroom 5, but no matter how I try to re-install it - from link adobe sent or from disc - all I get is "An error occurred when attempting to change modules". This is the first thing you see after entering the serial numbers. It looks different and nothing works. I have talked to chat at least 3 times and they finally admitted they know nothing. Can't talk to anyone by phone. So much for support for Lightroom.
Why can't you talk to anyone on the phone?
There are a number of possible causes for this. Not sure what happened with the Mac crash, but my first guess is that user permissions are currently messed up as a result. Try creating a new user account and see if you can launch Lightroom there.