Counter strike condition zero 1.6 problem..

Guys, can you tell me what should i do in counter strike but first my problem...
I just downloaded a ct pack (nothun wrong) the all of a sudden when i try to play, id just loads then goes back to the menu.
WTF?
If you guys have this problem and/or you know how to fix this problem, plz tell.
I just downloaded a ct pack (nothun wrong) the all of a sudden when i try to play, id just loads then goes back to the menu.
WTF?







If you guys have this problem and/or you know how to fix this problem, plz tell.