Hi Gary! Unfortunately, the only way to check your motherboard's memory slots is to place a working RAM stick into each one and see if your machine boots properly. Remove all RAM sticks and place one you know is functional into the first slot on your motherboard. Boot your computer. If it starts without problems, you know that stick and that slot are good. Power down and move the stick to the next slot. It sounds as if you've pretty much already done this.
I wish there were a utility to make the process easier or to confirm the results of your testing, but I'm afraid there isn't. :-(