I had this same prob myself. I could never get adb to work.
Navigate To:
Right click on My Computer>click properties>advanced system settings>environment variables> then double click Path under System Variables> delete what ever is there and put the path that leads to your sdk tools directory in there.
if you dont already know. to apply the new path, just copy and past whats in the bar above while in the sdk tools folder.
then it should work, it worked for me anyway.