Hi

recently my Asus P4T-E decided it's a good time to give up for good on me.
Before, everything worked fine. I could turn it on and it would POST normally each time, even with the cooler clamped on. After a few months of storage like that, the board would no longer POST by just pressing the pwr button. I had to apply pressure on the already clamped cooler for it to execute POST codes.
Now, it's not even doing any POST code execution even when I apply way more force on the socket. After a while, it just does the two-tone siren which wasn't there before.

My guess for this is either the s478 BGA pads got ripped or solder connection broke on them or BIOS got somehow corrupted (unlikely since before it fully died, it still worked fine).
Although, this is my second s478 mainboard which has these symptoms. First one is a MSI 865PE Neo with a similar SIO as this board (but this one is confirmed to have bad connection between socket and mainboard as I have to clamp the CPU for it to even come out of reset). I'm blindly shooting here but it might be somehow tied to the Winbond W83627GF dying. Tried heating the SIO, Asus monitoring chip and EEPROM to ~200C but it didn't change any behavior.

I don't have any EEPROM programmers at hand, so I cannot reflash the BIOS.

CPU Vcore on the asus is present, fresh CMOS batt is in place (even tried injecting 3.2V inside the battery socket), did a CMOS reset, tried different CPUs (Celeron 2.4GHz and 2.5GHz, Pentium 4 2.4GHz, all are verified to work), different PSUs, powering on just the mainboard, trying different fans, but nothing changed. Still the two tone siren and no POST codes.

Any ideas what else could be the issue?