Is this a new system you just built, or a CPU upgrade or what?
Can you list all the components currently involved (board and CPU we know, but how about PSU model or RAM kit model)?
Use the Flash BIOS Button to flash the latest BIOS version:
1. Download the latest BIOS from the MSI support site for your board and extract it.
https://www.msi.com/Motherboard/B650-GAMING-PLUS-WIFI/support
2. Take a USB stick and format it to FAT32 (it's best for it to have a size of 32 GB or less). You can also try
Rufus for formatting, as FAT32 non-bootable.
3. Rename the extracted (!) BIOS file to MSI.ROM and save it to the root of your USB flash drive / USB stick (not in a subfolder).
4. Plug the USB flash drive / USB stick that contains the MSI.ROM file into the marked Flash BIOS Port (!) on the rear I/O panel.
5. With the PC off, press the Flash BIOS Button, and the LED should start flashing for about 5-8 minutes and then the board reboots.
Under a minute of flashing, or more than ten minutes, and it didn't work. After ten minutes it will never finish, you can just turn it off then. I would then advise to try with different USB sticks, the boards can sometimes be annoyingly picky in which one they will accept for flashing.