Question No video with VGA beep code, but it works after Windows boots

[Kurochi]

CPU: Ryzen 9 3900XT
CPU cooler: Some 240mm Liquid Cooler
Motherboard: ASUS ROG STRIX B550-A
Ram: HyperX Fury (HX437C19FB3AK2/32) 3733 MHz
SSD/HDD: Crucial P3 Plus 4TB M.2 Gen 4
GPU: GigaByte RTX 4090 AERO OC (2 months old, Vertically mounted with a Gen. 4 riser, Gen. 4 mode enforced in bios)
PSU: Corsair HX1500i (2 months old)
OS: Windows 10

My computer worked flawlessly with this new graphics card for almost two months, but now I'm getting no video until windows boots. The funny part is that the bios even gives me the VGA beep code, but it doesn't hang, it still boots windows and I'm guessing it even loads the OS selection screen. After I either blindly select an OS or let it timeout, I'm presented with the login screen.

Clearing CMOS fixed this, but after I restored my usual settings (enabling TPM, CPU Virtualization, and setting PCIe to 4.0) it started doing it again at my second reboot. The first reboot after changing the settings worked just fine.

Does anyone have any idea about what could be happening? I don't think it has to do with my riser cable, it works 100% fine in games. Nonetheless, if you want me to do some PCIe bandwidth tests or anything let me know.

ALSO! If anyone has my same motherboard and could instruct me on the combination to blindly reset bios defaults I'd appreciate it, my case is wall-mounted and I don't feel like going through all that work to reach the clear CMOS jumper again... ❤️

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time?

the combination to blindly reset bios defaults
If you clear the CMOS, the settings for the board are all set to factory defaults.

 

[Kurochi]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time?

the combination to blindly reset bios defaults
If you clear the CMOS, the settings for the board are all set to factory defaults.

Edited with the list, left chassis and monitor out of the picture as they are irrelevant. I know what happens if you clear the CMOS, problem is that my case is wall mounted, and the clear CMOS jumper is in a very hard to reach spot, I'd have to remove the graphics card just to get to it. I've already done that a few times, but I really don't want to do it again unless it's part of someone's proposed solution. Which is why I asked if someone knew the exact key combination to press after entering BIOS, so that I use that even with no image and without taking anything apart.