95 Blazer issue please help
 

I recently replaced the ignition cylinder and key for my Blazer with OEM parts, original key would not disengage steering lock or start. My vehicle started and ran perfectly first time, now I get no dashboard indicators and engine won't fire. Radio turns on and light for transmission select turns on gauges work but no other indicators light up, as a result no fire. Battery is new and fully charged, fuses are all okay (tested) engine won't fire under boost either as no dash lights. Help please...