Windows 7 - <Quote> is currently unavailable

When opening the Desktop in Windows Explorer I get the following error along with my data:

" is currently unavailable.

Screenshot attached. Suggestions welcome.

Did you browse to the desktop entry and click on it?

Have you installed any theme programs that patch dll's?

What antivirus are you using?

I typically choose the left-most right-arrow on the address bar (shown in the attachment) and then choose "Desktop" from the drop-down list. I just now tried typing 'Desktop' (no quotes) into the address bar and I get the same alert box, this time containing "'Desktop' is currently unavailable." but I also get a new Explorer window with the Desktop listing.

I am using the default theme (I have 64-bit Ultimate, using Aero) and have not installed any other themes.

Antivirus is AVG Free.

Another datum: choosing 'Desktop' on the navigation pane does not give the error -- however, I don't typically use this, because this pane is very large and it's easier to do two clicks then to scroll up the pane.

Uninstall AVG free with a removal tool and install Microsoft's Security Essentials. Then reboot and see if the problem disappears.

That does seem to have fixed it. I'm surprised. Is AVG known to cause this kind of problem a lot?

EDIT: It's back... not related to AVG.

Spoke too soon; the problem has returned. Any other ideas?

Run sfc /scannow in an elevated command prompt. Type cmd into the start menu, then press Ctrl+Shift+Enter or right click and select run as administrator.

'

Do what Frost suggested,,,

For lack of better term.......

AVG is the epitome of GARRrrBage Anti Virus software.

Holy Toledo!

Ran sfc /scannow. Output logfile was huge and command completion reported "Windows Resource Protection found corrupt files but was unable to fix some of them."

Problem was not resolved. On the theory that whatever sfc *had* managed to fix was now irrelevant, I reran sfc /scannow (it gave the same command line output about "unable to fix") and saved only the new log output. It's attached. And *still* huge: 1700+ lines of what seem to be instructions to restore files. Is this utility supposed to run cleanly? If so, I'm assuming I'm looking at a reinstall...