Unknown total age, but has been operating fine for the last couple years of use. Recently, it decided to only wants remain on the "casual" setting and will not change to anything else selected. I unplugged it for 10-15 minutes in hopes to reset it, but it went right back to it after plugging it back in. Figure that it is some kind of board issue, but I was hoping that there might be some kind of hard reset or something.

Any advice is appreciated.

Thanks

Look at these: https://dl.dropboxusercontent.com/u/8010163/Whirlpool%20Dryers.zip
It is probably because your dryer is dirty and the sensors are covered with dirt. Tear it down and wash out the duct work and it will most likely work like new again. While you have it torn down check all of the thermistors and see what they read, if it has them. Some dryers have them and others do not. If it uses the button thermostats you may find one that is open. Check all of them.