I have Windows 8.
I had trouble getting rid of Bing Desktop.
I finally got rid of everything but one folder.
Even though I got Bing as a Windows Update, Microsoft said they couldn't help me.
I tried uninstalling on reboot apps.
I tried renaming it.
It also would not let me take ownership or give me permissions over it at all.
No matter what I did, "Full Control" and all the other options were grayed out & unusable.
There was a "USER" in the permissions box with a long string of numbers.
"Account Unknown(5-1-15-2-508114518....." and 20 more numbers !
This was the cause.
I was in despair.
I had moved it to the Desktop & put it in a folder.
I Zipped it & tried to delete the Zip file.
It wouldn't let me.
I put the Zipped version into the folder with the original file.
I stared at it for a while & got an idea.
I right clicked it chose Properties.
Then I Compressed it "to save file space".
It actually Compressed.
I dropped it in the Recycle Bin & emptied it & it was gone !
See this screen shot:http://i50.tinypic.com/a6z2d.png
I hope this helps people.