Without a doubt, a key finder program - a special kind of software tool - is the best way to go if you're lost a serial key for one of your software programs, so long as it's still installed or recently was. So what do you do when you can't find that special installation code but you need to install the program again? Where Can I Find Serial Keys and Installation Codes for My Software? Serial keys or key codes are often required during the first part of a program's installation or sometimes after using a program for a certain period of time.