Win 7 via RJ45 Null to XP to Internet via Sprint Tether

Hi all:

First visit in a while... With a question and I can't seen to find an answer.

My Story:
I live in the sticks (Country Life) and don't have cable or Internet providers.
I tried Hughs satellite internet for a few years. With all of it's downfalls I gave it up for what I have now.

I'm Grandfathered on an Sprint unlimited internet plan with my cell phone. I tether an XP system through Sprint's Smartview program. The program says it's Mobile Broadband.

A few years ago I bought an Acer Widows 7 Notebook but Smartview was not compatible and I had to upgrade to Win 7 Pro and set-up a Virtual Machine that ran XP to run Smartview in Virtual Mode to get online.

There were occasional (monthly) problems that caused me to have to re-install and lose information.
Finally I bought another XP Netbook and gave the Win 7 Notebook to my daughter.

There are things I want to do and needed a Win 7 PC so I bought another Acer Notebook with Win 7 Home Premium.

I have a wireless printer but if I'm online, Smartview disconnects with message that I can't access 2 networks.

Where I am now:
I have an RJ45 Null cable to connect the 2 PCs but haven't figured out how to set PCs to share files.
Also, when PCs are connected, Smartview kicks me off the Internet. (2 Network message)

How can set PCs to share files?
How can I have XP as host, Win 7 as guest and stay connected to Internet.
I would like to connect Win 7 through host to Internat.

Any help would be appreciated.

Thanks.
Richard