So I just put together a new build. I did this same thing 6 years ago with lots of help from here, and had no problems other than a faulty hard drive that hung during the Win 7 install.
This time after assembly I'm not getting anything. No beeps, no video input to the monitor, nothing. Power appears to be fully functioning as far as I can tell, it's just not posting to the UEFI (BIOS).
Here's my specs:
Motherboard - ASRock AB350 Pro4
Intended OS - Windows 10 Home - 64-bit - OEM
Those are all brand new. I also have the following used components installed:
CD/DVD Drive - LITE-ON DVD Burner
Rear Case Fan - Generic, scavenged 10 years ago.
Both of the used components were working perfectly 30 minutes before final assembly.
So far I've checked the following:
Tried hooking the monitor up to all video outputs on back of case (2 Mobo/ 1 Vid Card). Hooked monitor up to old PC and it worked fine. It has Auto-Select for which type of cable, too, so it should adjust to anything I tried.
Put the new HDD in old PC. It showed in Disk Management, but I couldn't find any info on whether that means it's healthy or not.
Checked all power connections. Like I said before, all power seems to be fine. CD/DVD drive opens and closes. Case fan, CPU fan, Vid Card fan, Keyboard LED, and Front Case Power LED are all on and working. I can even use the Power-Down function of the Front Power button to turn off the PC instead of having to yank the cord or use the PSU On/Off switch.
Checked all my Motherboard Header pins. As far as I can tell, they're all connected in the right places and seated securely. This Case did come with one of those unmounted speakers which is new to me, and I tried plugging that in both ways it would fit since my Case and Motherboard had different instructions regarding how to do it. Got no beeps in either direction.
Tried booting with only 1 stick of RAM: nothing again.
So that's everything I've tried so far. Whether this is a bad component, compatibility issue, assembly goof, or I'm not doing the posting procedure right, I'm under some time pressure. I only have 14 days left to take advantage of Newegg's free return & replacement policy, otherwise I'll have to RMA through the manufacturers. If I've forgotten any info you need, sorry, just tell me. I'll be grateful for any help.