The best first aid is always to run the install disk again. It will automatically run a repair utility that fixes most problems.

Failing that, uninstall the program, run RegCleaner to wipe out any registry issues, then re-install. (Don't worry. This won't affect any work in progress.)

And, if all that fails, post a message here describing your exact symptoms and the specs on your computer (particularly what version of Windows you're using). We'll do what we can for you!