Re: Want to install Natty... but partition issues :(
Yes you can install to an external. Do NOT let the installer install grub on the MBR of your internal. Grub should detect and boot your MS install from the external. For some reason that works better than trying to boot from one internal to another.
I would check your bios and see if you can disable the internal during installation. Then you have no chance of screwing anything on your internal at all.
Make sure that you change the bios so that it boots from the usb device first. That way if the external is off or not hooked up you will boot from the internal and if the external is there you will boot from it.
Dell 480 XPS 3G ram Quad Core 2.40GHz, Radeon HD 2400 PRO, Audigy1, 3x320G HDD, 320G External, Debian Testing for use, Debian Squeeze for secure use, Debian Sid for FUN