Dead computer, pls help

[TheViking]

Hi,
I recently opened my computer to try and fix a vibrating harddrive.
Before opening the computer i removed the electric cable but left the rest connected. When i was done i plugged in the electricity again and tried to start the computer.

The cpu fan spinned for one second then died, this is totally normal for my computer when i have had it unplugged. Usually i just hit the start button again and the computer boots. This time however nothing happens. Nothing at all, no fans spin or anything.

I have checked that the start button is correctly connected to the motherboard, and it was. Otherwise i wouldn't probably have got the fan spinning on the first try.

What can be the cause of this?

I have an asus motherboard which indicates if it's getting power by lighting a blue logo. It is blue so it seems like it's getting power.

Help is greatly apriciated

[Google]

Did you replace the hard drive?

[TheViking]

no,
I have got recommendations to test my psu by shorting the green and one black connector on the 24 pin contact.
The Psu fan did not start nor did the other fans connected to it.
Is the PSU the cause of my dead computer?

[Google]

I am not too experienced with these kind of problems so hopefully someone else will respond as well, but I would suggest testing your PSU and then replacing it if defective.

[archangel]

Did you replace the case cover? Sometimes there is a safety switch which will prevent the system from turning on while the case cover is off.