sorry to hear about your accident.

try a factory reset, hold down 8&16, Rock, Ballad and Jazz buttons and switch on. Do this first.

there are some others tests to try:

take out any EW boards.

1 hold down keys D3 and D4, switch on, anything in screen? then switch off.
Wait a few seconds.
2 repeat with keys E3 and E4 - press auto sweep.
3 repeat with F3 and F4 - press demo then panel set for left/right led check.
4 repeat with G3 and G4 - lcd test
5 repeat with A3 and A4 - ok confirmation
6 repeat with B3 and B4 - press test with blank floppy in drive.

if this does not work get in touch and I'll send you some special self extractors to try re-installing the o/s.

at least then you'll know if it is the hardware.

No responsibility is accepted for anyone else who chooses to play around with the above.

good luck!