For versions of Windows prior to Win 7 our standard advice was to run fdisk /mbr and then re-image the device. However, I believe that fdisk is not included with Windows 7.
Since Microsoft has removed Fdisk on Windows 7 and replaced it with another utility, if you type fdisk in the Start search box in Windows 7, it will prompt out Create and format hard disk partitions option and lead you to its new added feature Disk Manage
I'm trying to format a windows 7 boot partition using a bootable thumb drive but FDISK that I copied from 98 doesn't work. I believe this is how I used to format XP machines back in the day.