I've got a home-built desktop computer with a P4 2.8 GHz CPU in it. I've found that, when I ask it to do anything the least bit processor-intensive, it will eventually freeze and will not re-boot until it cools off. I assume the problem is that the CPU is in a heat-fail mode. I'm in the process of assembling a new Quad core machine, but I priced P4 CPUs and found I could get a 3.4 GHz for $125 from buy.com. This would make for a speedy machine for some of my non-video applications, including musical scoring, etc. A couple of questions:

1. Does my diagnosis sound correct?
2. Do all P4s use the same socket configuration?
3. Does $125 sound good for a 3.4 GHz P4?

Thanks!