98 cav wont start
 

my wife was driving to work the other day and her car started to over heat. she pulled over put some coolant in it let it cool down a bit and started friving again. so she called me i came and looked at it. when i got ther it had been sitting for about 15 min with the hood up. the motor was extremly hot and the radiotor was cold as ice. so i figured it was the thermoste. we let it set all day wher it was and i picked one up after work and put that in and alos put the recomended cootant in it. started it up and down the road i went. never started to over head (but i didnt have hot air coming out the vents when i turned it on). as i turned intot he town i live in the temp gauge shot to below 100 and the car died. i restarted it and it was was real choppy. as i was driving downt he road just to get to my moms house if i didnt keep the rpms up it would die so i got going about 30 mph and i put it in nuetral. pulled in the drive way and my mom said she heard something that sounded like a slapping belt. when i put it in park it died again and i opened the hood and white smoke rolled out from underneth it. from hat i have been told if i blew the head gasket on the front side there would be "milky" oil. if i blew it on the back side it would of went in my exhaust and there was no smoke, fluid or any condensation in the exhaust pipe. then i was told it woulda been the timing belt but i have no idea how to check that. i was told to take the distributor cap off and turn the key over and have someone watch it and if something in there spun the timing chain was ok and if it didnt turn the timing chain was broke......anytruth to that and how would i go about checking it