Newbie Internet / Networking blues

Hi all.
I need some serious help please. I recently bought a Acer Aspire One A110L netbook and cant seem to get my updates to work.
I am an absolute novis at Linux and i'm finding this very frustrating to say the least. :cry:
My problem is that when i tried to use my Vodafone E220 3GHSDPA USB modem to connect to the internet it did nothing.
I then read that you have to download the updates via wifi first to get the netbook to pick up the modem.
So off i go to a wifi hotspot and begin to download these A patch updates. Problem is ... when it gets to the end it gives me an error message saying that the
connection is lost or not connected etc. and so i try the updater again and same thing happens and nothing gets installed. Over and over again! :cry:
So in my brilliance i decided to try set up a lan via my desktop computer which is running windows XP home and my lil netbook via a direct cable.
But being a newbie to all this, i cant seem to get the netbook to pick up on the internet connection and i assume that its because i have to input some settings?
Please can some one help me to:
1) Explain why my netbook wont just update and install like a good little netbook, which would then allow me to use my modem and life would be bliss?
2) How can i set up a basic lan connection between my two computers with a cable so that i can attempt to do the updates once again, via lan connection?
I have a basic dlink network card in my desktop machine, and 10m of networking cable. :shock:
Any assistance would be highly appreciated.
Thanks, Kevin (SA)