solenid under the hood, jump it with some jumper cables and if nothing happens, you have a battery problem.make sure its in park.tap on the starter with a hammer and then try it.you might try to start it in neutral.
To the joker that suggested going to AutoZone for their free check..get a clue. They don't know squat about old cars and this one isn't able to be driven. You need to insure each and every connection is good and proper. All it takes is one faulty connection. Be patient and you will solve it.
well, there could be many things a wire would be the first thing i would look for, do this look at the starter solenoid now follow everything from the starter to the coils through the grounds, now look at the distributor, a ground wire could be vital in a situation like this, you haven't given very much info on this subject so im just doing the best i can, look at the battery i know gmc made a huge mistake when they made the clamps they like to come completely off sometimes even when they appear to be as tight as can be so check all the electrical over again, if nothing happens i suggest grab a hold of a diagram, and pull it out and put it all back in again.....max