If it's 2 years out of warranty sadly there's probably not much that can be done other than trying to get the powers-that-be to prise open the cheque book for a replacement!

If the dead board is a 680 it's worth considering an 880 board as a replacement - they'll often fit in the same space on the wall, have a hard surface with multi-touch and can still (legally) be used with exactly the same software. If budgets are tight also take a look at 480 boards - they're only single-touch but again have a hard surface.