A question about Trialkeys, and upgrading.

Alright, I've been playing Guildwars since Prophecies, I've gotten Factions aswell.
So now that I've beaten those two 100%, I've decided to get Nightfall.
It was going to be a day before I could go out and get it, so my friend let me use his trial key. I've made a Dervish, got it to level 11 today but now I want to know..

If I add a real Nightfall cdkey to my account will that character stay?

Also, if I add the CDkey to my account while the Trial is still active, will it somehow mess up my actual cdkey and somehow void it out? As in not being able to play it after the trial is up?

Yes ur character will stay on ur account.

Im not sure about the latter but i dont think it would make any difference to be honest, you new Cd key will supersede the trial one.

Thanks.
That's good to know.