Unmount it. Make it not a system, active partition. Just to say, Windows built in backup is really crap and Norton Ghost is cleaner. Windows will just clog up your backup.
It's because the computer wants to boot from the first primary partition on drive zero, which happens to be your D drive. you might try swapping which ports they are plugged into and see if that helps.
D: drive status is System/Active ... .. because there are the bootfiles (bootmgr and others). for a complete restoration of a working windows these files are essential and win saved them too.
easy fix is remove the 1.5tb from the machine, and re-install W7 with the 250gb only. After installation, put your 1.5tb back in
I fu**ing hate when this happens. Vista always did this to me...for some reason it would put its stupid boot files on drives that had no OS on them, or on a drive other than the one it was installed on. Dual booting was a huge PITA. like the above poster said, the easiest, fool proof way to get around this garbage is to unplug every drive you have except one during installation.
The most common reason for why windows chooses to make a system drive for a hadddrive other than the one containing the C:\ partition is that you have both IDE and SATA harddrives and you're either set in BIOS to: -boot IDE but have Windows on a SATA drive -boot SATA but you have Windows on an IDE drive When that happens, Windows is compelled to install itself on a non boot-compliant harddrive and so it uses a boot-compliant drive to install the boot routines, which then pass control to the drive you have Windows on. Obviously the drives will have to differ. Set your BIOS to boot off the same type of drive as you're installing the OS off(unless you have other OSs on other drives) then either migrate the boot routines or reinstall Windows. To migrate the boot files, do the following: -rightclick your C:\ drive in disk management and set it as active -set your boot device to the other type of drive(IDE or SATA) in BIOS -boot from the Windows DVD(note that at this point Windows will NOT BOOT ANYMORE) -copy the boot folders and files onto C:\ (bootmgr and whatever else is on D that has system attributes, best to google these folders) -if Windows fails to boot on the next restart, repair startup. Sometimes the MBR just needs to be rebuilt DO NOT DO THIS IF YOU HAVE MULTIPLE OPERATING SYSTEMS. It will break them.
I once used a really nice freeware program that was made specifically to do this sort of thing but for the life of me I can't remember what it's called. It would rebuild MBR, transfer boot files, etc. It was made for Vista if I recall but it works for all versions I'm sure.