Oo Er, Bad Luck! Normally a great piece of kit.
My Psion 3a manual is open in front of me and the first thing it says you should check is that your screen contrast is fully up! (Psion -> or Psion -<.)
Check batteries? (I know you'll have done that but I'm only repeating what it says in the manual!)
Soft reset - done.
Hard reset - Press and hold Right Shift while you first do the paper clip trick and then turn on with On/Esc. Lose all data sure but what else can you do? You may already have lost it anyway as part of the crash. I've never had to do this.
Good Luck! fob