Alright, you're probably running Home Premium as it seems like that's what most consumer desktops are coming with.
You said that you updated your video card. What video card and what drivers? If you updated drivers did you uninstall the original drivers first? Have you visited the website of the computer (not video card) manufacturer and checked for all updates for your new machine? I know you said you already got Vista updates.
Since you say you are having trouble downloading the "patch" then I assume you already downloaded the game itself? Are you letting the game download and install the patch or are you manually downloading the patch yourself? If so, exactly what happens - is Internet Explorer itself freezing up or is the whole pc locking up?
Lotsa questions but there are alot of things that could be going wrong. One thing to try is simply to delete and reinstall the entire game all over rather than messing around trying to patch what you have.