Vista - Maplestory issues

I used to be able to play maplestory fine on vista before, but now its a different story.

When I load maplestory, it comes up with a message about compatibility issues and so I press 'run program' in the hope that I will work, and it does, it gets to the log in page, but when I type in my ID, i can hear the music begin to jump and freeze, also words repeat, e.g if i press .net, it comes up with .neeet.

sometimes if I am lucky, I can get through, and once I am playing I am fine, but if not, the whole games freezes, and I have to reboot my computer.

Is there any way of fixing this issue?

P.S I have done all that, run as administrator, compatibility as win Xp stuff, personally I think its to do with Gameguard.