help, no video and power button stay dark

[lemonade_29]

Yesterday I took my GPU out of the tower to take some picture of it, and after I put it back in, there was no more video output. When booted, the GPU fan was starting and stopping every second, and the power button never lit up after press. When I tried the long press shutdown, the PC just boot up again. This is a 2011 HP PC with a after purchase PSU and GPU (7770), and I have followed the sticky.
Can someone clue me in on what might be the issue? Thanks in advance.

 

[alexoiu]

Make sure that the RAM modules are properly inserted (re-seat them). Same for all cables/wires.

 

[lemonade_29]

Rechecked, problem persists.

 

[alexoiu]

If starting the board with only CPU and CPU fan installed (RAMs, GPU, HDDs removed), does the CPU fan spin without restarting?

 

[lemonade_29]

Yes it spins without restarting if only CPU and CPU fan is connected

 

[alexoiu]

Now add the other components one by one and test after each installation. See which one is the culprit.

 

[lemonade_29]

At what stage should I expectany sort of video output?

 

[alexoiu]

One RAM module and graphics card installed.

 

[lemonade_29]

In that configuration there is still no video ourput and the gpu fan is restarting constantly. Tried various ram and slot combination .

 

[alexoiu]

Are the PCie cables connected to the graphics card?