When you run the Windows 11 PC Health Check app, what issues does it indicate are wrong? Has your friend configured TPM 2.0 in the BIOS? When you RUN tpm.msc in Windows 11, does it indicate that the status of TPM is "ready for use" and the Specification Version is 2.0? I assume you know what I mean by RUN (right click on the Start icon and left click on Run). it should say something similar to this:
What other issues does the Windows 11 PC Health Check app indicate that prevents you from updating Windows 11?
You indicated your BIOS is up to date with the latest BIOS version installed for your motherboard. When you go into Settings and click on Windows Update -> Check for Updates, what error messages are you receiving or does it provide an option to install Windows 11 24H2?
Just so it's clear to me, when you run winver, what version does it indicate?
If everything is good when you run the Windows 11 PC Health Check app except for the CPU, you'll have to reinstall Windows 11. You should back everything up to a different drive. I bought an 18TB Western Dighital Gold Drive so I had a lot of room to backup and save everything as well as have a place for all my apps, downloads, photos, videos and everything else that was important. That drive is normally only used in data centers but it lasts almost forever. Just copy all documents on your boot drive especially under the User Folder that you want to keep to the new drive. When you're copying files, make sure you go into File Explorer and select View -> Show -> Hidden Items as you may need some of the hidden files as well when you restore your system. Before you do a backup, it would be best to cleanup your system. One folder that definitely needs to be cleaned is %temp%. Just select all (Ctrl-A) and press Delete on your keyboard. A few files won't delete but that's fine.
You can also cleanup everything with apps like IObit Advanced SystemCare Ultimate. Pretty cheap and it works great. Another one that's great is IObit Driver Booster which will update all your drivers on your Windows system to the latest versions. You can download the free version to see what drivers are out of date. You'll probably find a lot of drivers need updating. Anyway, what I did is I copied EVERY file from my boot drive to my new 18TB backup drive so I had a complete copy of everything that I was allowed to copy. Some files are being shared by the operating system and won't let you copy.
When you reinstall Windows 11 completely, a folder will be created by the installer called Windows Old. Many of the files will be in there that you can obtain when you want to restore your documents. It's a lot of work but it's definitely worth it.
Let me know if you have any questions or problems,
Chuck