Hello, Taylor LaRocca

Welcome to the Microsoft community.

I understand that you are experiencing a problem with your monitor's HDMI, and that this problem could be due to a number of reasons. Given that you've taken some steps to troubleshoot the "no HDMI signal" issue without success Since you've tried different cables, monitors, and even replaced the video card, the problem could very well be elsewhere. Here are some troubleshooting options:

Cable/Port Issues: Although you've tried changing cables and monitors, make sure the specific HDMI ports on your computer and monitor are working properly. If there are other types of ports (e.g. DisplayPort, DVI), try using an appropriate cable or adapter to see if you can get a signal.

BIOS/UEFI SETTINGS: Occasionally, BIOS/UEFI settings may be restored or changed, causing problems with display signal output. If BIOS/UEFI can be accessed (using another monitor or video output if necessary), check to make sure that the correct graphics output is selected (e.g., prioritize PCIe graphics over integrated graphics).

Memory problems: You mentioned that the problem exists even after replacing the monitor Faulty or improperly installed memory may prevent the computer from booting properly and thus providing a signal to the monitor. Try reinstalling the memory stick, or if there is more than one stick, try booting with each stick individually to troubleshoot a memory module failure.

If, after trying these additional steps, you still face the problem, it may indicate a more serious hardware failure that may be related to the motherboard or even the CPU. If you are unable to troubleshoot these components on your own, you need to consult a professional computer repair service to diagnose and fix the problem.

Please let me know if you have any other questions or if I haven't explained something clearly.

Best Regards,

Aaron- MSFT | Microsoft Community Support Specialist

I'm unsure if this will help anyone, but on my laptop, in Device Manager, Windows 11 had disabled both of my Display adapters: AMD Radeon(TM) Graphics and NVIDIA GeFore RTX 3060 Laptop GPU. I right-clicked on them and clicked Enable, and instantly my monitors connected again.

For me, I don't think an update caused this, but rather I was already connected to my monitors, and then they suddenly disconnected. I'm not sure the cause. Hope this helps someone.