I was trying to remove the cog on my Motobecane Messenger today to put on a newer cog, removed the lockring and put the whip on and couldn't budge it no matter how hard I tried. So I put the wheel back on to reverse rotafix it and the chain snapped on me. Haven't had the bike for more than 6 months and it only has 2-300mi on it so far. The lockring was loctited on and I can only assume that the cog is too. Is there any way I can get this off without going through more chains?

Thanks for any help,
John