How do I get rid of this thumbnail on my Windows folder?

[Megalith]

I'm at a complete loss as to why a random image has associated itself to my Windows folder. What is more frustrating is that there seems to be no way to remove it, as the Windows folder's properties menu doesn't have a "Customize" tab that allows you to reset a folder icon.

I have tried deleting everything in the AppData\Local\Microsoft\Windows\Explorer folder (although, for whatever reason, I get an "access denied" error when I try to delete iconcache_16.db) in an effort to purge any and all thumbnail caches, but the problem persists. Does anyone have any suggestions? I'm all out of ideas.

 

[adamf]

You could try this Icon Cache - Rebuild - Windows 7 Help Forums

 

[alphanumeric]

Look for a hidden Folder.jpg file in the Windows folder. If it's there, just delete it.