Oldsmobile/Buick Repair: electric problem, sudden discharge, ground cable

Question
my 98 blazer would not start i cleaned the side terminals on battery and it started. what would cause the speedometer, temp, fuel gauges, and radio memory stop working? i tested the inside fuses and fuses under hood all have power both sides. the gauges temp & fuel reading on the high side, speed reads "0" and no pindle markers "p-r-n-d-3-2-1" the truck was running fine. also, alt., and oil temp gauges work. Any suggestions?  

Answer
hi wendall.wow bad news,if you unhooked the cables with the key on .this caused a sudden discharge of capacitors that control these components...or if you unhooked the pos side of the batt first even with key off.the spark from the memory.could damage the body computer .but try this.unhook the ground cable for ten mins and rehook.sometimes this will reset the puter.if not then puter or dash must be repaired.sorry wish i could give you better news but sugar coating will not fix it good luck.please take a min to rate my service.ty billymac