No signal after changing CPU

[hfffoman]

I guess this is the classic situation where the system powers on but doesn't do anything. Before I give up and replace the motherboard, maybe someone will have some helpful insight. Here's the story.

I swapped out my drives to SSDs and reinstalled Windows 10. All worked fine. Then I decided to upgrade the CPU. Now there's no signal when I turn it on, and no beeping. The motherboard lights are on and the fans spin on the CPU and the GPU. I put the old CPU back in and it still gives nothing. I can't think what went wrong between yesterday when it worked and today when it didn't. I ran the vac inside but was careful not to damage anything. I took out a couple of DIMMS to get access but the slots are clean and I put them back properly without damaging them. Obviously I opened the CPU cooler. Interestingly, I did it as a test before buying the new CPU - took the old one out and put it back and checked everything worked (just for a minute as the thermal seal was broken).

I have done the following checks:

Unplugged the power and held the power key for a minute.
Removed the GPU and plugged the monitor into the onboard graphics.
Verified the monitor and cable works by plugging it into another machine.
Removed the CMOS battery for a minute.
Removed the RAM. No difference - it doesn't beep.

Specs are:
Motherboard: ASUS P8Z68-V LX
CPU: i5 2500, replaced by i7 3770.
Power: Corsair GS800
RAM: 4x4GB COrsair DDR3
GPU: GTX 760
Case: Antec with lots of fans

I have a feeling this is going to be bad news. If I have to replace the motherboard I probably wouldn't get one with socket 1155 CPUs in newer sockets are better value, but now I have just forked out £250 for a CPU.

Thanks for any help

 

[alexoiu]

The board would need a BIOS update for supporting the new CPU. Try reinstalling the old CPU. Check with single RAM and graphics card removed. Test each RAM slot.
If internal speaker connected, test with no RAMs. See if any beep.

 

[hfffoman]

I can't install any CPU as it won't do anything. It put the old CPU in and it no longer works. I will try each RAM slot. With no RAM, there is no beep.

 

[alexoiu]

Check the CPU socket. See if any bent pin.

 

[hfffoman]

Ok, I have tested it with no RAM and with a single DIMM in one slot, for each slot. The result is nothing every time, not even a beep. Looking closely at the pins, it is hard to see. Mostly it looks fine but if I catch the light at the right angle there is a clear sparkle in a couple of places which could be a bent pin.
That would make sense given that swapping the CPU is the only thing I did between it working and not working. On the other hand I didn't touch the pins and placed the CPU carefully. It sits snugly in the right place and there is no way to locate it incorrectly. If that's the problem is it worth trying to tweak the pins with a tiny tool under a magnifying glass?

 

[alexoiu]

Can you post a picture of the socket here?

 

[hfffoman]

I looked under a strong magnifying glass and there were definitely a few bent pins. I have just been working on straightening them. It is very difficult. A toothpick is way too thick for the task. I found a minute screwdriver which worked reasonably but it was really difficult. The problem is it's very hard to see what's going on as the pins are slanted. The slight errors of alignment are only visible at just the right angle and then when I bring the screwdriver near I can't see the angle any more. Anyway I spent half an hour trying to correct them, with 3 LED lamps shining in from different directions. It looked much better after I did that, but not perfect. I then tried to boot up the PC and it didn't work. It gets to the point where it's easier to install a new motherboard.

 

[alexoiu]

It seems so.