I had the same problem with my GC-Prevue install when I came back to work after Xmas and New Year hols - simply wouldn't run and gave no error. Looked like I was going to need the new $50 GC-Prevue as the totally free one has adverts and no measurement capabilities.
However uninstalling my current version and then downloading and installing V25.4.5 (32bit version) and V25.4.7 (64bit version) I got back up and running with either. I assume since support for these ended in Dec 2017 at some point soon I will be required to do the upgrade to the $50 version.
We also have Viewmate available, but I have used GC-Prevue for more years than I care to remember and so am very comfortable using it. At least the $50 is a site-wide licence