I have an 93 olds 88, previously my grandparents vehicle, my grandfather replaced a head gasket 2 years ago on it and put it back together and it hasn't turned over since he is 76 yrs old now and never felt like bothering with it after the head gasket replacement. When I turn the key the dash lights and fuel pump and etc. come on, but there is no power to the starter, therefore won't turn over. Checked all fuses and relays and starter connections, all good. What should I do next?

Ok first things first, is there power on the big red power wire going to the starter? If not check the positive battery terminal they're known for getting corrosion between the two stacked terminals and having trouble. Then get under the car and have someone turn the key and see if you have power on the smaller solenoid wire. If you have power on the heavy red wire but nothing on the smaller solenoid wire you may have a security problem. These keys have a little pellet chip in them and sometimes the ignition won't read them anymore. The car goes into anti theft mode and won't crank. Its very easy to bypass though.

Agree......With a test light attach(probe) it to the big red cable to the starter solenoid and see if the test light lights....if it does, now attach the test light to the little purple wire going to the "*" terminal of the solenoid....be careful, in case the car decides to crank......there should be no power on the purple wire, until someone turns the key to the crank position......if you have power, you need a starter.....if no power, then turn the key to off.....Look at the dash, and just turn the key to the "on" position.....watch the SECURITY light.....it should come on for three seconds and go out......if it stays on, you have a problem with the Security system.....If it goes out, after 3-5 seconds, then try starting the car in neutral, with your foot on the brake......if it still doesn't start, then you have to check the wiring between the starter enable relay(sometimes the relay goes bad), the P/N switch, and the starter solenoid....

First step, would be to feel the starter enable relay, and when the key is turned to the crank position, it should click.....if it does, then you need to see if you have power out of the relay....if it doesn't you need to check the control circuit to the relay and the controlled circuit of the relay.....