my d/a sander was in a flood now it won"t work, can it be ?

In a flood? It got submerged in dirty water?

Could very well be corrosion.
Corroded contacts preventing the current from reatching the motor.
Corroded bushings preventing the motor from turning.
Whires corroded so badly that they broke off.
It can also be filth and various contaminents that need to cleaned out.

If there is at least some "humm" when powered on, the current is passing. Corrosion is jamming it in place. UNPLUG IT ! You need to open it and generously lubricate all bushings, gears and pulleys. Obviously, don't lubricate any belt nor any pulley's groove...
Manualy make each part move untill they move with only minimal effort. You probably need to take it appart to do so. Take some photos and take copious notes of how everything is assembled before removing any part.

If there is no current, call an electrician to redo the whiring and replace switches.

Electro
September 2015