hai ,friends i tried to use boot camp for install win7 for dual boot. But install or remove windows is greyed out and downloading windows software takes ages to finish so i downloaded windows support .dmg from other direct link and have it. I tried refit also. Nothing helps. Please guys help me out i am not familiar with mac osx i wanna use windows for autocad software. Thank you in advance. I have windows 7 disc with external drive too. I am using macbook air 1,1 with os running lion 10.7.4.