Where's ej gone?
Scylla, what follows is based on my own playing around with Unetbootin and so on - just remember I'm the board's perpetual beginner...
Unetbootin is useful for allowing one to try out various distros - it gives you a live CD on a stick (USB flash drive). It doesn't actually install the distro. It just lets us run a live CD on machines with no optical drives. The "iso" file that would normally be written to the live CD is written to the flash drive, which Unetbootin magically makes bootable.
With this in mind, there's probably not that much point to using a whole 80GB drive for Unetbootin experiments. Any distro that fits on a CD will fit comfortably on a 1GB flash drive; those requiring a DVD for a live disk will need a larger flash drive.
I've only used Unetbootin on Linux machines, but I assume the Windows version is similar. The trick is to set up Unetbootin (which you've obviously done), then to download and save the iso files of the distros you want to try - I put mine into a folder called "iso folder" 'cos I'm such an imaginative chap.
Plug in a USB flash drive, point Unetbootin at the iso you want to try, check that it wants to install it to "USB flash drive" or whatever it calls it, and let it go for it - quick and simple.
Reboot the computer, tell it to boot from the USB drive and you will soon be playing around with a live CD (which is actually your flash drive.)
If you then want to install the distro on the flash drive, you do so from the flash drive just as you would from a live CD.
If I've read it right (apologies if I'm wrong!) you want to install a Linux distro to your 80gb external hard drive. I take it you don't want to leave the drive plugged in permanently for a "dual boot," but merely wish to use it from time to time when it is useful to use Linux.
As long as your netbook can boot from a USB drive, I'd imagine this would be simple enough. What follows is what I would do - sorry I can't outline it in a couple of sentences. (Or find a suitable tutorial - bet I find one as soon as I've posted this.)
First, try a few distros from a live CD (or in the case of your netbook, from a live flash drive, with the live CD iso loaded via Unetbootin.) Once you've found one which both you and your netbook like, install it to the external hard drive.
Again, I'm assuming you don't want to dual boot, but to leave your Windows installation totally separate from the Linux installation on the external drive.
Temporarily remove the laptop's own hard drive. If you don't do this, then when you try to install Linux to the external drive, it will think you want to dual boot and set things up so that on start you can choose between the two drives. This will be fine until you try to start Windows on the built-in drive without the external drive plugged in. At which point the air will probably turn blue.
So remove your hard drive for the moment to protect it from your installer's enthusiasm.
Boot the netbook off the USB flash drive and check that your live session is working. Plug in the 80gb external drive. Your live CD/flash drive should see it.
Tell the distro you're trying out to get on and install. If it asks where, point it to your external drive (easily recognised from any options offered by its size if not its name - depends on the distro being installed. And don't be fazed by Linux's drive descriptions - it won't be drive C,D or whatever but something like sdb1. Whatever - it'll be easy to figure out which one it is. Especially if there's only one connected!)
The easiest option if you're happy to use the whole drive is to let the distro you're installing look after the partitioning for you. If its options look odd just say yes to the defaults. After all, your netbook's own hard drive is sitting safely to one side at this stage, so what harm could ensue? At worst, you simply start again.
Once the installation's complete, shut down (it'll need a reboot anyway), remove the flash drive and start the computer up - telling it to start from the USB drive.
If it starts up, You Have Won. Let it update.Set things up as you like them.
Shut down, and re-fit the computer's own hard drive. When you want to use Windows, let it start normally. When you want to use Linux, make sure your external drive is plugged in before you start, and tell the machine to boot off the USB drive. (Might take a little googling/experimenting to find out how to do that. With my old Thinkpads and Fujitsu, you tap F12 during start up to choose the boot device. The little Eee PC needs Esc pressing. Wish they'd all make their blessed minds up.)
Just a couple of points on downloading distros to try them out.
Try to download an iso (ej will explain what an iso file is...) for the distro you're trying. If you can only find an archive version (.zip or whatever), simply unzipping it should give you the iso.
Which distro to try? Paradoxically, one of the things which puts folk of Linux is the sheer volume of choice. Puppy is a great little distro. However, with your set-up I'd honestly go for something a little more "mainstream." Apart from anything, trying to install extra software to Puppy taxes my abilities to the utmost. It's a great live CD, but with your reasonably powerful computer and an 80gb drive, I'd go for a full-size distro.
http://eeepc.itrunsonlinux.com/the-news/303-5-linux-distros-for-netbooks-reviewed
is an example of articles dealing with suitable distros for netbooks. I'd also have a look at Ubuntu netbook edition:
http://www.ubuntu.com/getubuntu/download-netbook.
And quite honestly, looking at the specs of your netbook (way beyond any of my computers), why not try a few other distros? The time-consuming bit is downloading them to your hard drive. It then takes but a few minutes to use Unetbootin to load each in turn to your flash drive, reboot from the flash drive and give it a whirl. And when you find one you look, remove the netbook's hard drive and install your chosen distro to your 80gb external drive.
My own favourites are Mint, Mepis and Mandriva. G-C speaks very highly of PCLinuxOS.
Ubuntu is great if a)you like purple (or brown if you go for an older version) and b) don't mind installing an extra "repository" in order to find non- open source drivers. Mint tends to be Ubuntu without that particular hassle. Mepis has the unfriendliest looking user-agreement of any distro I've tried, but more than redeems itself with its incredibly friendly forum.
And you really want someone "telling" you what to try, I'd for Mint 8, Mepis and Ubuntu Netbook Remix (the latter cos it's specifically for netbooks.)
You'll also be confronted with a choice of windows managers/versions for some distros . Where this happens (eg Mint) I'd suggest the Gnome version as easiest (for my brain). KDE is almost as easy and slightly prettier (but not pretty enough to totally sway me away from Gnome). XFCE results in a faster distro - but your machine will handle the others fine - takes just a little more effort, perhaps. I have yet to suss out BusyBox..
The others should now pile in and explain why those are absolutely hopeless choices! Like I said - bit of an embarrassment of riches when it comes to choosing a Linux distro.
Sorry this was so long - no real way of keeping it short. And as I'm sure you'll gather, I've left a lot out - fortunately it's easy to work out the missing bits.
I really can recommend giving Linux a whirl, though, especially since it's easy to retain your Windows if you want to do so.
I didn't realise how many bookmarks I had in my Firefox Linux folder - but if I can find any useful tutorials I'll post them - they'll be simpler to follow and more complete than what I've offered here.
And if I've suggested anything dangerous or inaccurate, please would somebody comment?
Above all, though - have fun.