Yeah, my dads computer was still working, which was what was confusing the hell out of me. Turned out, he hadn't installed the latest KB update I had done, a day previously.
Theres been tonnes of forums shouting about it.
I only found it out though after ringing Virgin Media, and they told me about the patch fault causing it, so I did more research and found a new download for Zonealarm.
But, to get the Internet working first of all, I had to uninstall the KB update.
That's the bugger there
All is installed again now though, and working.
If anybody finds this and is also having problems with a computer, first go to the Control Panel.
Then go to Add/Remove programs.
Where it says 'Show Updates', tick the box.
Now, scroll all the way down until you find 'KB951748', and uninstall it.
Restart, and when up, the Internet should be back online.
Install the update, set it to just upgrade and not do a clean install to retain settings, and then you'll have to restart the computer again.
When up, Microsoft should find the KB update hasn't been installed yet (if you haven't got Automatic Updates on), and ask you to install it.
Install, reset again, and there you go.