1999 Isuzu Rodeo Question Won't start

I just bought this SUV. My son put in new plugs, we had a new radiator installed because the old one had a leaky patch job and we bought a new battery. I put less then 40 miles on it. Last week I went to an appointment sat there for about 4 hours drove home around 7 miles and noticed as I was parking the car read H. It was hot. There was no smell, no steam, smoke or noise. I parked and called my son. He came over and drained the radiator and was going to replace the thermostat but couldn't do it because of where it's located. So, he hooked it all back up and the battery. Now it won't start. We can hear the fuel pump come on, it sounds like it wants to start. He checked the plugs they are OK and getting spark. He said no fuel pressure. He checked all fuses and they are fine. Is it the fuel pump, filter what? This is my first car in 7 years I was so excited and happy not to be riding the bus and my 2 youngest, ages 2 and 4, were happy about going to the zoo etc. Please help! Thank you THANK YOU. Sherry