My PC suddenly doesn't recognize my BEST software.
Try applying an update to the application and then check its behavior. If it still refuses to run, completely remove the application from your PC and then install it again. It should work this way and it works for most of the apps that suffer from this issues.
Here is the website with the updates: http://www.brother-usa.com/support/ModelInfo.aspx?R3ModelID=SABESLET2