|I think this question was presented a little wrong.. okay, so your computer cannot boot and because you want to fix that, you want to transfer all of your stuff to an external hard drive?|
If it won't boot in normal mode, try in Safe Mode. When the computer boots up, press F8 and with the menu that comes up, select Safe Mode with Networking. That will allow external devices to be plugged in so you can transfer your stuff.
Did that work??