Have you dropped your phone or maybe exposed it to water? Sounds like something with your circuitry is fishy, or the button could be faulty as well. Worst case scenario, have it replaced under warranty. Maybe they'll even give you a Storm 2 instead. Never hurts to ask.
Personally I haven't had that issue. To downgrade your OS, you have to have an older OS package installed on your PC. When you connect your berry to the PC open Desktop Manager and click the App Loader. It will check your current OS and list any other OS packages found on your PC. Select the older one you want to load and kiss your berry buh bye for about 30 mins.
