On my laptop, my old HDD stopped working so I've replaced it with an SSD (WD Blue 3D NAND 2,5" 500GB). An local computer expert said it will be compatible. After inserting SSD computer launched smoothly. Installed Linux, restarted. When power button was pressed, nothing happened. Tried removing battery, holding power button for 30 seconds - powering up without and with battery - removing SSD - removing RAM. I've USED multimetr and now I KNOW that the computer power adapter works properly and that there is power in my motherboard.

So, on my old HDD BIOS was COMPLETELY different from BIOS on my new SSD. I'm unable to reset BIOS.

Please, help me, I'm desperate. A HDD does not change the BIOS...are you sure the Linux install completed > >
If not start over...Can you post the make and model of the Laptop please?
I wonder what you needed to dismantle to install the hard drive so the make and model should help.
With this info we can also check what lights maybe on the laptop.
 Hi
If it is the Asus Laptop in your specs can you first check the cable running over the hard drive is seated correctly at both ends. or as it is just for a couple of connections you could TRY it without the cable. also remove the usb board i have shown in the attachment to test you are not getting a short where the board and the DVD drive hard drive  are screwed thru.
Also do you get a power light and charging light indication?