It sounds like the computer (and everything else) isn't getting any juice. I would check the fuses first, followed by the battery, then cables, etc etc. Best case, you have a dead battery, loose connection or blown fuse. The worst case is rather unthinkable (dead computer).
I found that the shop manual to be indispensible in diagnosing problems. You might want to pick up one in the premium membership section... they can also be found for purchase on the net, but premium membership seems to a cheap way to get them.