LR Classic updated my catalog which it now says is corrupt and I can't open LR Classic at all

Yesterday 26/10/2024 I opened LR Classic and it updated the catalog because of a recent update. When I came to reopen later in the day, LRC says that that catalog file is corrupt and to use another catalog. Unfortunately after that error message came up, I cannot get LRC to open at all. In desperation I decided to uninstall and I keep being told to close down LRC (which of course is not open so I am unable to do so). I am unable to do anything at all. Please help

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