When you install windows, it automatically formats the drive and would erase all your data. You could try using software to partition the drive into two pieces in another computer. Some software will allow you to do this without removing your data. Once the the partition is made, move all the data to the back (2nd) partition. Re-install the drive to the intended computer and use the first partition to install the OS. I haven't used partition software in years, but I am sure there is some free software out there that will do the trick.