My old PC received the same message. I looked into the issue and tried changing the BIOS settings but it doesn’t support the required security level that MS require for Windows 11.
A new motherboard might well fix it. Obviously that is likely to need a new processor, new memory card, etc etc.
I’m annoyed by these more frequent mandatory obsolescences. This year I’ve lost the use of my GARMIN satnav after the latest update turned it into a paperweight. I’ve also lost the use of two identical GoPro cameras after they both decided to refuse to boot up after being put on charge. Especially annoying as I’d bought a new battery for the first one that failed, found it didn’t help, bought an identical camera to find exactly the same failure within a very short time.