If you have installed IE10 and you are running Visual Studio 2010, you may get this annoying pop-up.
"Attached the Script debugger to process '[1111] iexplore.exe' on machine 'MINE' failed. A debugger is already attached."
There is a simpler fix for the JavaScript debugging issue in IE10:
  1. Close IE
  2. In elevated cmd prompt run this command:

regsvr32.exe "%ProgramFiles(x86)%\Common Files\Microsoft Shared\VS7Debug\msdbg2.dll

or %ProogramFiles% on a 32-bit OS.

Hope this helps!