Restore Problem

i just restore my backup (C:) on my laptop compaq presario cq40..i save my backup in my externel hardisk.. restore process running smooth until "3 minutes remaining" and look like it stop running.. ive wait about 3 - 4 hours and it never finished till i gave up.. i plan to cancel/shut down my machine and want to format using windows 7 Cd.. but it says Bootmgr is missing after i restart my machine.. and it cant detect my windwos 7 cd..from my experince, it only takes 20 -30 minutes to finish restoring..

my question here is.. is my backup corrupted? if yes, what should i do..?

or

do i have any other options to solve my problem..

thanks in advance!