I have an HP tx2z laptop with a 320 GB HDD and decided to install Ubuntu 8.04(64 bit) onto it, but I wanted to put it on my external hard drive, 180 GB HDD(I think that's how big it is). I would've just done v9.04, but the install wouldn't recognize my external HDD, so I just went with the older one. I do guided install on the entire external HDD and ubuntu works wonderfully on it. So I decide to switch back over to vista; I power down the computer, unplug the HDD, and restart the computer WHEN... I stare at a message with some gibberish about grub step 1.5 and 'error 21' and the computer does nothing after that. When I start the computer with the usb HDD plugged in, however, it gives me the option to choose between the operating systems and Vista loads fine. I would like to just be able to run Vista without the external drive attached and just run ubuntu with the external drive attached. Please help!