Desktop diagnosing issues

[MAK725]

New to the site so maybe there is a thread somewhere where this is already answered but here goes...i have a 4 year old HP pavilion desktop im working on and it does not send video to a monitor. I replaced the vga cord and the vga to dvi adapter to rule that out. bought a gpu which did not change anything when added, hard drive light at top corner of tower does not blink or come on at all. No beeps at all. bought new hard drive, plugged it all in with a new windows 10 usb also plugged in, still nothing. This likely a motherboard or power supply issue? i saw the led for hard drive activity come on for the first time when i plugged in the new one and got an hp boot screen a total of 1 time when messing with the newly installed hard drive without the windows usb. and an error message once saying no windows disk found or it is corrupted when the brand new windows usb was plugged in. Any help is much appreciated!

 

[cin19]

We need you post the PC model or spec first so that we can take a look at the problem.

 

[MAK725]

HP P7-1512. Ive concluded that a power surge took out part of the motherboard because a new gpu and new power supply did not fix it. But bios successfully resets and computer resarts now (with new power supply) after following the instructions even without being able to see anything. Ill keep new power supply for now.