I think the only thing that can be said here, is Always Backup the Pro Installer.
This is just my opinion, but even if you did get in touch with LW, your complaint would Fall on Deaf Ears.
The ONLY way for this to have happened was that You D/Led an Updated Version of Basic and it Deleted your present version of Pro. Thats the way it is Designed. Its Really No ones Fault but Yours.
So you've had a Pro Version for several years and you prolly paid about $18. and some change, Right ??
Now Figure out How many Files that You have Illegally Downloaded Due to Copyright Infringement, for the said Price of $18 Dollars and some change. Now do you Really have Room to complain ?? I think Not.
If so then Buy another Pro Version and Be Happy.

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I Don't Suffer From Insanity, I Enjoy Every Minute of it