I have a problem. i have a laptop "hp probook 4510s" and the hard drive is crashed so it dosen't have any internal harddrive. i have taken it out of the computer and waiting for a new one. but in the mean time. ive read about VHD.s for windows 7. but it is one thing i don't get. can you start Windows 7 by using VHD on external hard drive on a computer that dosen't have an operating system? or do you "must" have one in order to start windows 7 from vhd? when i tried and booted from the external with windows 7 ultimate installed on it it just said "BOOTMGR Is Missing" So is there a new to start a computer with windows 7 on external hard drive? please help? and sorry for my bad english. Regards!