AMI BIOS memory failure
Award BIOS keyboard controller failure.
Phenix BIOS has "set CPU speed
The PC chips M520 normally uses an Award BIOS (at least mine does) but keyboard controller failure should not stop the board from posting. This AMI memory failure is not listed as critcal either, the critical memory faliures that hinder a board from posting is 1, 2 or 3 beeps with an AMI BIOS, not 1 long and 3 short beeps .
Phenix BIOS has "set CPU speed" listed as 2-1-1-1 which I guess is the same as one long and 3 short beeps.
Check your jumper settings once more and repance the memory with yet another set if you have more spare modules, try another CPU if you have one.
Get a diagnostic post card, they make it a bit easier to find out what is wrong, as a bonus you get a small manual that lists beep codes. In general a beeping board is a good sign, no beeps is much worse when it comes to boards that fail to post.
New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.