Texturepack

#1
Hey when ever I log in to any server I accept the texture pack and the game crashed, I assume its because the texture pack is in way too high definition for my computer to handle, So I denied it this time, and I read the starter book, it said to do /usepack [low/medium/high] and its not letting me, it is saying unknown command.
 
#2
Hey, I'm not sure how helpful it is because I already have the pack on automatically and I couldn't remove it to try this but do /rp. A GUI opens, hopefully you can click on the pack and it will install. Hope this helps!