Powerbook G4 Freezes and Fan Doesn't Come On

[flight3]

It freezes sometimes during start up and if it makes it past that, it will work for about 15 minutes before freezing. Now before all of this happened, it got hot one night and then it told me to shut it down holding the power button. After that I realized that my battery seemed to be messed up or something because it was getting hotter even if it wasn't plugged or turned on. So I switched batteries and now it doesn't get so hot, but it still gets around 127 fahrenheit (checked using istat app). Now I don't know what to do, i've tried that fsck code and the computer worked for almost 2 days and now its back to freezing. I noticed that the fan has never come on during any of these times, and it doesn't make any sound at all, so I don't know if its broken or not. Also I noticed that when I turn it on and hold down the "S" key it seems to always make it past the start up. Any ideas???