Choosing bootloader for Ubuntu alongside Windows 7

Solution 1:

Since sda is MBR(msdos) partitioned, Windows is the old BIOS/MBR boot. And then you want Ubuntu installed in BIOS boot, but have boot loader in same drive as Ubuntu, and keep Windows boot loader on Windows drive.

Only if installing to sdb which is gpt partitioned, you will also need a 1 or 2MB unformatted partition with the bios_grub flag.

Just use Something Else install option and choose correct drive (not partition) on the partitioning screen. Do not use any auto install option as that will install grub to drive seen as sda, overwriting your Windows boot loader.

If no Windows skip those screens, but partitioning screenshot shows combo box at bottom for drive to install grub bootloader, choose sdd if that is drive you are installing into:

How to use manual partitioning during installation?

After install set BIOS to boot from drive you installed Ubuntu, or sdd. But it will show drive by brand/model not sdd.