MG Car Repair: stuck between gears?, shift lever, gearbox

Question
i have a 66 midget (actually an A-H Sprite) that i think might be stuck between gears ... engine runs fine, can't get it into gear.  any thoughts on how to troubleshoot?

Answer
Hi DJ,
To test it, try to shift into gear when the engine is off. If you can, and it grinds when the engine is running then it is the clutch not the gearbox. If it will not shift into any gear when the engine is not running then it is the gearbox. If the shift lever will not move, you should try removing the small tower around the shift lever to see if anything is wrong in the shift tower. If nothing can be found there you need to remove the engine and transmission to gain access to the gearbox.
Howard