Once you've found the serial numbers and product keys for your programs, print them out and keep them safe! You probably won't want to go through this process again next time you reinstall a program.
Tip: Didn't find the product key or serial number you were looking for? Try another free product key finder program. Magical Jelly Bean Keyfinder is great but if it doesn't find the key or serial that you're looking for, it's not of much use. Another free key finder program might do the trick.

