There are various ways in which computers are set up to enable boot from a device other than the hard drive. The most common is to go into the BIOS and change the boot order but it's not the only way.

On my laptop there is a message that appears briefly on startup that says something like "Press F10 to change boot order". If you do that you get a menu of the various possible devices you can boot from.

It looks as if your netbook works in a similar way. So; Insert your USB stick into the computer, start the computer and press F9 as instructed and see what happens. I suspect that either it will boot directly from the usb stick or you will get a menu which allows you to choose from the available possibilities.

Just try it and if it works, then that's the way you get your computer to boot from a usb stick and you don't need to worry about editing the BIOS so you can go ahead and install Ubuntu.

BTW, the Wubi business is a bit of a red herring. Wubi.exe is a windows installer which is invoked if you choose to install Ubuntu within windows. It sets up Ubuntu as if it were a Windows application. It's useful for trying out Ubuntu over a longer period than you might from a CD or usb stick. It's how I started with Ubuntu and it's possible to move everything to a dedicated Ubuntu partition later but it's a bit of a pain to do and there's a risk you'll lose data. It's how I first started with Ubuntu but really it's better to do what you are proposing and set up Ubuntu on a separate partition from the start. The point is that you don't need to worry about it. It's there on your usb stick by default for anyone who wants to take that route but you don't need to use it.