Question First half pc build-(No response from pc)

Jun 26, 2019
Hello everybody,
Yesterday my pc came from Turkey without power supply and pc case because of dangerous reasons an. Whatever there was a HP 3120 mt computer in my house and I replaced every parts of that pc with my pc which came from Turkey except psu. I connected all the cables (I guess) but after pressing power button nothing happens even any lights on motherboard. I am sure that psu was working in my old pc and after connected power cable I can clearly see that psu lights turn on. But as I said after pressing power button nothing happens even power supply fan and other components doesnt work. I will response all our answers as quick as possible. Thanks for helping.

i3 540
gtx 750
mini atx motherboard
8 gb ram
and psu from hp 3120 mt

Kawaii Penguin

May 21, 2015
What I'm seeing through this post is that you put all new parts from a computer you bought online (that doesn't include the case or PSU), into this pre-manufactured computer:
HP Pro 3120 MT - Pentium E6600 2.06GHz 2GB 320GB Micro Tower PC

The micro-tower ("MT") is very small, and has a very limited working space, for starters. You would've been much better finding a case online that had a pre-installed PSU for around $80-100.

The two most common problems when it comes to a bootup failure:
The cables were mismanaged and not installed correctly.
A faulty component from ESD or from the factory.
The PSU may not provide sufficient power to the computer components.

And a variety of other things.
Probable causes are bolded.
I'm under the assumption that you winged this for the most part. Cable installation is much harder than most people would think, albeit it is easy once you get the hang of it.

A very common mistake, when wiring, is not placing the 1-pin prongs into the correct slots that is meant for the case functionality. Please look at your motherboard's instruction manual and look at the part where it goes into detail about the 8 or so slots for the case functionality pins that are required to properly give the command to start up the computer. Compare the exact location and purpose of each slot to the 8 or so 1-pin cables that the case provides. If the computer case is old, you may not be able to even see a label on the 1-pin connectors. There are connections for power negative, power positive, shutdown, etc.

Another possibility is that the PSU you provided does not provide sufficient power to the GTX-750 graphics card that you fitted onto the board. This appears to be a computer meant for a workstation, so naturally, the PSU won't be providing that much power to handle a high-tier graphics card. Also, HP sucks. A lot. Their quality is rather garbage.
Note that the power requirement for a GTX-750 graphics card is about 450 watts. A computer like this (meant for workstations) is more than likely going to have a lesser wattage provided to the tower.

The only other issue I can think of would be that you may have accidentally fried a component due to electrostatic discharge. This only happens when you don't wear an electrostatic bracelet and you have a charge within your body that discharges upon contact with the surface of any electronic module within the computer.
If you don't use a bracelet and connect yourself to a piece of metal that's connected to the ground ("grounding" yourself), you put yourself at a high risk of discharging your bodies electrostatic into the components. This risk is amplified if you're wearing clothing that has a static tendency, like pajamas.
This cannot be fixed. Once it happens, your components are fried. That's that.

Since it seems you may be new to this, I advise seeking a local computer shop to handle this for you. Their prices are around $80 for services around where I live in the United States.

Anyways, there's a few pointers for you. I wish you the best of luck, and remember that google is your best friend.