I had same problem and i solved it look you need to go to Shortcut Arrow - Change, Remove, or Restore - Windows 7 Forums and find [FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]3.To restore Defauld shortcut Arrow [/FONT]and download that .reg file and right click on it and click "Merge" then click run,yes,yes,ok and restart computer then try to pin to taskbar ... it worked for me i wish that work to you too 
