The spring may be snapped but if you can still feel it pulling a little then the cord has probably just wrapped itself badly round it's spool. This often happens when people just let go of the starter cord and it snaps back too quickly into the housing.
To sort the above problem out, just try pulling the cord all the way out (you may need to pull quite hard) and gently letting itself feed back in. If this doesn't work then remove the spool housing (it's usually held in place with 4 screws at the back) and you can visually inspect the mechanism.
Replacing springs is fiddly. Here's a hint for you. If the spring has come loose, fit the outside end first, then carefully wind each coil in making sure it all lays flat so it stays under control. when the last (inner) coil goes in, it won't need to be held in place any more and you can replace the spool.
javelin10
August 2010