Topic on Talk:The Elder Scrolls V: Skyrim
After looking into this a bit more, I found that Nvidia appears to have changed the URLs for all of their previous guides. For example, Koroush's Battlefield 3 tweak guide changed
from this URL: www.geforce.com/Optimize/Guides/battlefield-3-tweak-guide
... to this: www.nvidia.com/en-us/geforce/news/battlefield-3-tweak-guide/#1
In this example, the first URL redirects to the second. So it's possible that the Skyrim tweak guide still exists on the Nvidia website but the redirect wasn't set up correctly. If I'm correct, one option is to figure out where the new location is.
Edit: Also, I'm pretty sure that part of Koroush's arrangement with Nvidia at the time was that he sold his rights to the guides that they published. So he can't request their removal even if he wanted to.