clutch help plz!

hey there ppl i have just bought a r 19 16v k reg, i was driving it the other day and i span it out off a junction. then as it was spinning it jumped out of gear and now when i put it into gear (goes in fine) it dosent move, at first i thought the clutch has gone, but then i spoke to a friend and he said it could b the sirclip come off the final drive! anyone got any idears or an easyer way to find out wots up without taking the gear box off?

many thanks jay!