Hey ppl, i need a little help. You see ive been thinking about getting the Online game Called Guild Wars. Problem is, i know very little about how to install it. I tried doing some research.. but all i saw was GW faction, Gw Nightfall and so on.. There were so many!? so confuseing.. So please please please!! Tell me which one is correct to buy, so i can start playing

Ps: What is the difference between them all? Or are they all expansion packs?

I am looking forward to seeing some answers, im dying to know