I cannot open Lightroom Classic. I've tried "SHIFT ALT" and tried opening but that didn't work. Please help! This has been going on for a month and is very frustrating.

You might be having the same problem as in this forum thread-

Open Task Manager, [Exit] from all listings of Lightroom-Classic, Open LrC (once only), wait and wait.  See what happens.

(   [Windows key + X] > [T] will also open Task Manager.  )

Many others are complaining that Lightroom does not open, but it is actually opening in the background. You should check that with Task Manager (ctrl+alt+delete)