Switched out processors, now I have no display

[Bleckworthy]

So I ordered a new processor for my pc, core 2 duo, and replaced my old one with it. I already checked it out and talked with Intel, the processor is supported.

So I took out the old processor, put the new one in, applied artic silver 5 paste appropriately, and yadda yadda.

Put the heatsink back on, screwed it in and now:
When I turn the pc on, everything turns on, all the fans, all the motherboard lights, HDD's, but it won't send a signal to any monitor I try it on.

Ok so I totally removed the heatsink, and then it worked again. Turned on the PC and I got to the Bios and windows and all that, but quickly turned it off because it hit 86 Degrees Celsius.

Ok so I tightened the heatsink again, and then it didn't work. No monitor signal.

As soon as I loosen all the screws, it works again, but as soon as I tighten them, I get no monitor signal/display.


One time, I lightly tightened the screws and turned the PC on and it worked, but as soon as I tilted the Tower Rightside-up, the whole PC locked up because the processor was knocked loose.


So this clearly has something to do with the way the heatsink is sitting on the CPU after it's tightened. Any Ideas?

 

[nikorr]

It looks like it is shorting somewhere.

 

[nikorr]

BTW, whats the mobo and old and new CPU?

Stock CPU cooler?

 

[Bleckworthy]

Intel® Desktop Board DQ965CO Motherboard.
Old processor was an Intel Core 2 Duo E6420, new one is a Core 2 Duo E6700.
I already know they are compatible.
The cooling is part of a MPC Client Pro 385 Computer Tower.