Okay so i install morrowind, tribunal and then morrowind, int that order, but when i go to start the game and it say something about an error, that snowflakes wont load, i don't understand this, i tried all sorts of stuff. I'm usually pretty good with this stuff but this doesn't make sense to me.

sry, morrowind, tribunal the bloodmoon

Read this mate it's a very common problem;

http://forums.uesp.net/viewtopic.php?f=5&t=16173