Starting with the drive letter, what's the FULL path to your data file? And to the backup?
Nothing strange there.
So, please try holding the CTRL and Shift keys while you click on the Q program icon. This should open the program with only the FILE and HELP menus available but NOT open a data file.
This test will help to determine if your issue is program based or file based.
Did the program open as expected? If so, restore from that backup via FILE, Restore a Backup File.
When the program shows the whirring icon, is the data file size getting bigger and bigger?