Windows 11 installation recurring nightmare!

Hi, what is your current full build number? (The forum did prompt you...so we don't have to ask...).. - e.g. 19045.3570

Major upgrades can fail like feature upgrades for many reasons.

I assume your PC is fully compatible and you've run the check- it should pass as you've been offered the upgrade.

Have you run basic integrity checks?
Check disk e.g. Hard Disk Sentinel (inc. SSD).
If ok run
chkdsk c: /scan
from an admin command prompt.
If ok, likewise run
SFC /SCANNOW

Check it passes.

Before making changes, secure your system by ensuring you have a current 3rd party disk image - saved on an external drive- so if something goes wrong you can recover.

You should uninstall AVG completely - and use the manual uninstall tool. Leftovers can cause upgrades to fail.

Ensure you have at least, say, 40Gb free on C:

Once you've done that, and secured your system again by creating a current disk image, try updating again.

It may well fail.
This time run

setupdiag.exe (free from MS) and post the log.

You can also look at
setuperr.log
setupact.log

I get an update every few days saying that the system will upgrade me to Windows 11, it loads, I restart my machine

You can stop that behaviour quite easily.
Search the Tutorials section for
target feature upgrade
and specify your current major build (whichever that may be).

have fun setup as admin that often works

Is the computer the one listed under "My computer"? If not, what are the computer specs?

Please post a whole window Disk Manager image of ALL your drives. Don't forget to expand the columns so we can read them. How to Post a Screenshot of Disk Management
If you have a MiniTool or AOMEI Partition use it instead or Windows disk manager.

Await response to my post #2. Thanks.

Given that your Recovery partition is the first and only one, the build number is of interest.

Also a Disk Management screenshot using Minitool Partition Wizard as Megahertz recommended.
Why? 1 partition isn't shown by Disk Management (by design).

To see your current Windows, open a CMD window as administrator and type:
winver

To see all the partitions on drive 0 type (on the CMD window as administrator)
diskpart
sel disk 0
list part
exit

Take a snapshot of both (Winver and diskpart) and post it here as an attachment.

Dalchina already asked so please:
Open a CMD window as administrator and type:
chkdsk c: /f
It will say your disk is in use and ask if you want to schedule to next start = yes
Restart

Back to Windows, open a CMD window as administrator and type:
sfc /scannow

If it finds any corrupted files, fixing or not, reboot and run again

Then run
Dism /Online /Cleanup-Image /ScanHealth
and
Dism /Online /Cleanup-Image /RestoreHealth

Await reponse to the rest of my post #2 +#6. Thanks.

Another thing you might try- if your Windows partition is the last on the disk- shrink it by, say, 1Gb to leave some unallocated space at the end of the disk.

Did you do the system check?

Open a CMD window as administrator and type:
chkdsk c: /f
It will say your disk is in use and ask if you want to schedule to next start = yes
Restart

Back to Windows, open a CMD window as administrator and type:
sfc /scannow

If it finds any corrupted files, fixing or not, reboot and run again

Then run
Dism /Online /Cleanup-Image /ScanHealth
and
Dism /Online /Cleanup-Image /RestoreHealth