Switching between 2 players

[Nyalan]

I am trying to play with my friend's account for fun and to make him some levels ups, but when I select his character it kicks from the game and tells that this character belongs to someone else. I have installed his version of mount and blade on my computer, but now I can't play with mine. Strangely, I think I was able to switch between my character and his on his computer. Should I install 2 versions of mount and blade?

[Jarlek]

It all depends on the CD-key. Change the CD key to your friends and it will work.

[Tears of Destiny]

Don't play other characters that are not yours, as that is multiaccounting and thus bannable.