I just had to change the bearings in my 96 s 10 blazer and it ran before i took the motor out and we got it back in but there is no spark or the fuel pump dont turn on when i turn on the key. I dont know what to do. i dont know if it is just a ground wire off or i was told maybe a bad crank sensor. Any help would be nice.

 

If it ran before, then chances are that you have left something disconnected (it's easy to miss something)
Crank position sensor makes sense, check connectors to CP sensor and to the disrtibutor.
Spend some time going over the engine compartment looking for disconnected connectors......check your underhood fuses also.