Hmmmm......................

The machine won't boot but the lights come on, and the fans spin? That doesn't sound like the CPU to me..................with an old machine I still go for a dead CMOS battery.

If you have a multimeter/battery tester or know someone who does then check it out.

Better still, remove the battery and take it to the shop where you would buy a replacement and ask them to test it for you to see if you need to buy a new battery from them