SkyNetRising :
Install disk would let you fix bootloader and if that's not enough, then it would let reinstall windows.
Yes i know, just wonder why the op drive is no longer detected, data corruption, you may fix with a system disk/usb but if the drive is not detected to start with, we are looking at something else. If he/she just reset bios maybe and now won't boot, just needing to restore those settings. I am not going to suggest getting another win 7 install till i know these basics are checked first