Sorry to hear of your issue. If you do not have any system restore points, then, as far as I know (and I am not an expert), you are pretty much stuck. There are programs that will recover files, but none that I have heard about (so far) that will re-install programs that have disappeared. Did you check the Control Panel (Uninstall Programs) to see if the program is still showing as installed? If so, is there a "Repair" option if you click uninstall? Some programs come with a repair capability to repair the program files and registry entries if something has become corrupted.
Personally, I rely on full system images done weekly on both of my computers, plus daily backups of any changed data files. Nothing "forgets" faster than a computer. Backups are really worth the effort. There are lots of great products out there (Easeus, Macrium, etc.).
Hope this was of some help. Have a great day.