Problem with start up after renewing some components

[Hihrii]

I had a HP-PC and I decided to get new power supply and a GPU, that required that I had to buy new case too.
I moved the parts from the old case to the new one with bigger power supply, and then mounted the new GPU. But now, when starting up computer only shows the HP logo on a blue background. There's a text that says "press esc for startup menu". When I press it, nothing happens... I don't understand, in my mind it should work like before, cause I didn't change the HDD, or anything.
Can you help me? Motherboard is H-CUPERTINO2-H61-uA TX

 

[knightdog56]

Check for a misplaced standoff or a I/O port being shorted on motherboard.

 

[PallindroneT3604]

Does your keyboard work? Maybe a bent pin if you a PS/2 or a bad battery in the wireless...also, if it is a USB wireless, make doubly sure it's enabled in the BIOS and that USB devices boots up as well upon POST. Just a couple of ideas here....