Just upgraded 7 to 10, Documents don't show up in This PC/Documents

If whoami identifies your username as 'Administrator' then find out what other accounts exist by entering net user in a command prompt and posting the results [because then we can tell you which entries to ignore - it's quicker than writing it all out in advance].

What account were you logged into on Windows 7? From what you have just posted, I think you mean that you were also using the built-in admin there.

There is no need to use this account. Being connected to the internet whilst the account is enabled creates a hole in your security. Anybody could be doing anything behind your back and you would not know a thing about it.

Do you have any idea how you came to be using the Built-In Administrator account?

Check Settings, Update, Activation. If you are activated with a digital licence then you might as well back up all your own files & application installation files & application product keys then reinstall Windows 10.
- I'd suggest a WD "offline scan" as soon as installation is complete.
Windows Defender Offline Scan - TenForumsTutorials
- Before restoring your backups afterwards, give the backup disk a full antimalware scan.
How to Scan with Windows Defender - TenForumsTutorials

Denis

Yes, you're in the right place. Activation is shown in the diagram you posted [in the left-hand column].

Your Marc account still exists. Let's have a look at its properties. In any command prompt, enter net user marc and post the results.

And the whoami command confirmed the username as Administrator? [that's Administrator in full, there would be nothing wrong with you calling an admin-level account by a name such as admin. It's just that the username Administrator is reserved for the Built-In Admin account and it's that that I'm reacting to with such concern.]

Denis

That activation type [which is the same type that most of us have] means that you can reinstall Windows 10 without having to worry about any product key.
- The dialog that would let you enter a product key also has a button to bypass it
- Your Windows would simply contact its Activation servers the next time you went online, find the record of your current activation and re-activate Windows. All without any action being needed on your part.

Your Marc user account has admin status. It can therefore be used for such jobs as authorising application installations.

Your whoami results confirm that you are logged in to the Built-In Administrator account.

Opinions differ, as you can see from the @Bree post above, but
1 You have spent periods online whilst logged in as the Built-In Administrator,
2 [Personally, even having that account enabled whilst spending time online would be a concern,]
3 You do not know how you have ended up like this,
so I am concerned that your computer might have been infiltrated and malware planted.

I already know that @Bree disagrees so you might wish to wait so he can post again, but I think the only safe course of action is what I said before -
- Back up all your own files & application installation files & application product keys
- Reinstall Windows 10
Clean Install Windows 10 - TenForumsTutorials
- I'd suggest a WD "offline scan" as soon as installation is complete.
Windows Defender Offline Scan - TenForumsTutorials
- Before restoring your backups afterwards, give the backup disk a full antimalware scan.
How to Scan with Windows Defender - TenForumsTutorials

Denis

Yes. The only thing to consider is whether a newer Version has been released since you made your original installation disk [you are on ver 1909 & that remains the latest version]. And that would not be catastrophic, it's just that you'd then end up repeating Version upgrades when you could have clean installed straight to the current version. If the USB was made recently & is what you used to upgarde to your current Ver 1909 then just use it.

If you are not sure about the USB then I can look up some notes I think I have about how to check its version.

Denis

1 To check the USB, go to its Windows\System32 folder. Right click on the file ntoskml.exe, select properties, look at the Details tab & check its version number. You can do the same with the file on the HDD as well. This is mine & I am on ver 1909 -

- Note that this check cannot tell the difference between Ver 1903 & Ver 1909 because they use the same core elements. They are both reported as 10.0.18362.NNN {the last bit merely indicating which Cumulative updates have been installed}.
- I got this check from TenForums user @jdc1

2 Remember that you will not use the same procedure that you did to upgrade from Win7. You'll use Clean Install Windows 10 - TenForumsTutorials which will overwrite the whole of the disk.

Denis