So, I've used Ubuntu for a month or two in dualboot with Windows 8, it looked and ran fine, however it broke down for some reason and I had to restore the entire PC. Due to this bad experience, I decided to reinstall Ubuntu on an external hard drive separated from my main Windows machine. This option seems to be good for both the operating systems.
However, when installing Ubuntu, for some reason, the bootloader Grub was not installed on the external drive, while at the same time, the "old" Grub bootloader was never erased from the PC internal hard drive. As a result, I am in a weird situation: when I want to run Windows, I just power on the pc and go. When I want to run Linux, I have to plug in the external drive, go in the startup menu, and change bootloader from Windows' to Grub. The external hard drive is not bootable (as a usb stick for example) and this long sequence of operations needs to be repeated each time.
- PC internal hard drive contains Windows OS, Windows bootloader and Grub from the old linux installation.
- External hard drive contains Ubuntu 15.10, possibly Grub, but is not bootable as a USB stick is.
- Every time I want to switch OS I need to change bootloader manually in the startup menu which is tedious.
- Boot devices are ordered as follows: 1. USB 2. External drive 3. Internal drive
My question: How can I make the external drive bootable so that when I want to switch from Windows to Linux I just power off the pc, plug in the USB, power on the pc and go? (without loosing the data I already stored on it and all the preferences)
PS. For some reason Windows is terribly slow when loaded via the Grub bootloader available in the internal drive. Furthermore, if the external hard drive is not plugged in, Grub bootloader shows the Grub rescue panel only. So using the already installed Grub as the only bootloader is not an option.