manual transmision when I press in the clutch I hear a slight chattering noise while the engine is on

When I press in the clutch I hear a slight chattering noise while the engine is on, also, it feels as if the transmission is trying to engage even though the clutch peddle is fully depressed. Once I take it out of gear the transmission will not go in to any gear unless I shut the engine off, then restart the engine in the gear selected.