Confused with Winpe entry in easybcd.

Hello fndz! How are you? Hope All u r fine right now...ok fnds i m in a Porblem or u may called it a Confusion.i m a new user of easybcd. I want to install windows 8 or windows 7 through booting from boot.wim. So i Add a new entry to boot.wim & reboot it. Then Windows Setup Starts but unfortunately it says Drivers missing. I don't realise why it Says Drivers missing! Cause it works fine when i boot from Pendrive or bootable media. Can u Say Should i wil be able to install windows 7 or 8 by Adding entry to boot.wim using winpe entry in easybcd?