CPU Power Connection
Your CPU will need its own power. The power connection comes directly from the power supply and is much smaller than the connection you connect to your computer.
You might have everything installed correctly and still hear and see your computer power up, but it will not post unless you have power running to the CPU. The older computers with older CPUs never required their own power.
But all the modern day CPU’s are very powerful and need to draw their own power from the supply rather than through the motherboard.
The same can also be said for hard drives. If you are using a SATA hard drive it will need its own power. Unlike M.2.
Not Checking Heat Temperature After Install
After you have built your computer and installed your operating system like Linux, Windows or OSX if you are building a Hackintosh, you should always test and see your computers temperatures to make sure they are running at acceptable levels. If they are not you should stop immediately and re-think your options.
Most reputable motherboard manufactures will come with a disk of utilities which usually include hardware monitoring tools. Install them straight away and see if your temperature fall into acceptable levels before going any further.
Screen Plugged Into On Board Graphics
If you have bought graphics card for your computer, that is the output connection you need to plug into your computer screen.
Most times your motherboard will automatically choose your graphics card over your on board graphics. Your computer will still boot up, but if you have your monitor plugged into the on board graphics instead of your graphics card you will not see anything.
Also, sometimes moving the monitor to the graphics card will not always work. If so, move the screen cable to the addon graphics card a
Making Changes While Power Is Connected
I know this seems like an obvious one, but it happens so often.
Not only is it very dangerous to work on a computer while it is turned on, it can also completely damage and ruin major components like hard drives, Processors and specially motherboards.
A sudden surge from electricity or sending a signal to the wrong component at the wrong time can cause it to be damaged.
A good example of this is hard drives. They hate to be turned off without shutting down properly. Even if your computer is finished and your computers gets turned of incorrectly due to power loss can result in the lost of damage or your hard drive becoming RAW – corrupt.
