I have the same problem. Windows Defender finds SurfSideKick over and over
again but always fails to remove it (same error message noted below). I even
just upgraded to the most recent release - same issue. I had to go buy
Spyware Doctor to remove SurfSideKick (it's a particularly nasty bug that
constantly hijacks your browser - both IE and FireFox) after Norton
AntiVirus, Windows Defender, and XoftSpy all failed to get rid of it. Even
now there seems to be some disabled remnant on my laptop since WD keeps
"finding" it (and erroring out when trying to remove it).