I upgraded my laptop with an SSD, moving my old HDD to where the DVD-drive was, so that I could have speed and storage. Now, I have reinstalled Ubuntu on the SSD, deleting all the partitions on the old HDD to make space for a data partition. But now the laptop doesn't even get to GRUB 2 if the HDD is plugged in! If I take it out, everything works, but as soon as I plug it in and retry to boot, I won't find GRUB. At first, I thought it was because of the boot order, but the order was OK: first the notebook hard drive (SSD) and then the CD/DVD drive (which in reality is the HDD). How can I fix it? Doing a simple grub-install /dev/sda doesn't work.. The SSD is sda, and the HDD is sdb.