Capture One 21 Fujifilm Crashes on opening

I have previously had trial versions of Capture One Fujifilm Express and Capture One 21.  I paid for Capture One 21 Fujifilm.  On opening it crashed repeatedly.  I have uninstalled and reinstalled with no change to the cash issue.  In desperation, I reset my PC to factory default and reinstalled- The issue remains.  I have tried deactivating the other licences on the trial software, with no change.  The suggestion of presssing Alt on opening makes no  difference.  I am unable to access any settings in the programme to make any other changes as it will not open!  I have emailed Help/support 3 days ago and had no response.  Any suggestions would be very much appreciated.