When I installed Ubuntu on my laplet (Tabtop?), I very explicitly selected my USB drive as the destination for GRUB. The laptop is natively a Windows 8 machine, and the idea was to not even touch the native bootloader, and instead have the machine boot to Ubuntu whenever I had my USB drive plugged in. Should work in theory.
Naturally, post installation, I tested this by removing the USB drive, and sure enough GRUB fired right up. Adding insult to injury, GRUB isn't able to boot Windows 8 at all, leaving me with an Ubuntu-only machine on a primarily touch-based device. Not fun.
I'm pretty sure I can figure out how to get Windows fixed; my issue is that it shouldn't have happened in the first place. Did I miss some magic checkbox in the installer? Is the installer perhaps bugged? (This was Ubuntu 12.10 btw.) There's a step in the installer where you select the destination for GRUB, and I checked and double checked that I had selected my USB drive (The same drive the installer itself was running from) for the install and it didn't complain. I'm not sure what I did wrong.