If you want to try the Beta version, you can just install it over the top of your current version. However, if you want to go back to the original version, it's best to uninstall the Beta first, then reinstall the original, either from the CD or our core software download on the website. I tend to recommend downloading it from the website as it sometimes has a newer non-beta version than the CD, depending when you got the camera.
Unfortunately though you can't have both versions at the same time, running or installed to switch between. Am I remembering right that you have an Infinity? If so, I think you might find you want to stick with the Beta anyway!
Hope that helps,
Jo