Samsung Galaxy Prevail / Precedent

I had some trouble with my Prevail also but (this is astonishing) it seems that keeping it in a pocket or purse without a cover causes a problem with the keyboard. I was keeping it in a briefcase and carrying it on a plane and the phone got jostled around between things. One night I couldn't get it unlocked. the bottoms keyes kept flashing. I took on the battery rebooted multiple times, etc. The next morning everything worked fine. I have kept in in cover when travelling and never had another problem.