Hi Dave
In the bottom of your cash register near the back is a hole that has a botton or a lever that you can actuate the mechanisem to open the cash register. Provided that register is not manually locked.
If all fails and you are unable to open it, I'll be happy to buy it because I have all the keys on the similar register that I use in my business. My email is shahrammouzoon@yahoo.com.
Good Luck
Shahram Mouzoon
March 2007