Review your backup situation. A backup file may be your solution. Did you write one to your flash drive or other media? Copy what you have so that you don't overwrite something that may prove useful.
I would try a Standard level 2, and if that does not fix it, a level 1 repair. The level 1 will delete any customized reports.
You might get by with File->RepairMoneyFile->QuickFileRepair.
If that does not do it, restore a backup file that predates the problem. Rather than restore to the remembered filename, browse to your Documents folder, and choose a new filename. That will keep you from overwriting your existing *.mny file.