sueco2003 wrote on 2025-05-03, 14:38:

Hello, I have an Asus A7V600-X motherboard and it is not posting. The PSU is not faulty... […]
Show full quote

Hello, I have an Asus A7V600-X motherboard and it is not posting. The PSU is not faulty...

I have run the pc in many situations and thus I can conclude some stuff:
- The PC only beeps once if I don´t plug any RAM.
- The PC is on for a second and then it shuts off (with or without ram).
- However, if I put the CMOS jumper on "reset" mode the PC doesn´t shut off, but I can´t see nothing on the screen nor do I hear any beep.

I put a new CMOS battery and the symptoms continue. The capacitors look fine for me. Can it be a BIOS issue? If yes, could I flash it through an USB (since getting a floppy nowadays is really hard ahah)?

What do you think the problem can be? Thanks in advance.

The start-stop cycle problem is not easy to fix (the system changes its state). The mainboard "doesn't like" something: some voltage or just measurement of some voltage, some reset signal is active or something prevents the signal to get inactive.
You may do some easy but important to diagnostic things: scrutinize the board for scratches or other damages using magnified glass, test (maybe with a finger - be cautious) temperature of chips after some time of being powered on (they shouldn't be scorching hot).
Then, a PCI debug card would be very helpful to understand if the CPU runs BIOS program.
I don't know if it is possible to recover BIOS from USB stick or from floppy.
Good luck!

New update. now the motherboard keeps beeping forever, like beep ... beep ... beep ... beep ... I have searched the motherboard manual and found no information regarding to that. Does anyone know what it could be?

sueco2003 wrote on 2025-06-01, 13:52:

New update. now the motherboard keeps beeping forever, like beep ... beep ... beep ... beep ... I have searched the motherboard manual and found no information regarding to that. Does anyone know what it could be?

It may signal about RAM problem. Try to compare the behavior with and without DIMM. Try to clean DIMM contacts, to set into another memory slot.
If you have a multimeter you can try to measure some voltages that is for DIMM