What you need to do is identify your chipset. It will be something like Intel 965 but you must make sure (you can use software like Sandra to help you, here's a link to a 64bit version :SiSoftware Sandra XII 2008 (13.12) download from Guru3D.com) . Then go to the Intel website, here's a link for the chipset software page Intel® Chipsets Support - Home

Choose your chipset and follow the links, there is support for 64bit and what looks like a 'install utility'. This utility will probably un-install your old drivers and then install the new ones. As for which driver is which, chipset drivers include USB drivers, ethernet, in fact basically everything other than graphics, which as you say is Nvidia. I don't own a Intel board nor would I want to advise you on what to uninstall, why not try a Intel forum? Good luck

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Hi! I don't know if any of this will help, but I'll give it a try. Here are some links to check out. It starts out with the 32 bit, then details into your 64 bit. Server Products - Available Memory Limitation When 4 GB Installed [PDF] (Number 2) Windows Vista: 64-bit Editions