Do not have a bootable image on the flash drive as izvestno, you can just copy the contents of the installation disk Windows installation to the root of the stick/HDD, saprosites with her and start recovery console (after selecting language). In win7 recovery console is a complete command-line version (I think, sorry if mistaken), with some extra utilities. That's where it will be the most bootrec.
In your situation, you need to type bootrec /fixmbr to restore the booth and record Windows. If that does not help, try the bootrec /fixboot, but then it will overwrite grub.