The upgrade was not botched, i built the computer myself, and have been doing so for a decade. Ive read of people that had problems with the game in the past with nividia cards, and the game ran great until i upgraded, and again yea i uninstalled the drivers correctly.
Surely i cant be the only one
Also uninstalled the hd texture patch thinking it had something to do with it, no changes.
That's odd, I had the 301.41 drivers and Skyrim ran fine on my GTX 670. I just installed the latest beta drivers and it still performs good. After you clean up your old driver bits (Driver Sweeper is good to use for Nvidia drivers.), try OC/downclocking the card. Still odd that it is giving you issues.
Since you mentioned odd shadows and such, is the card overheating? use MSI Afterburner and/or GPU-Z to monitor the temps. You can also run a Furmark burn in test. Another thing you can do is run a memtest to test the integrity of your RAM.
I've never had issues with my GPUs with Skyrim (old SLI GTX 560 Ti, now GTX 670 w/ single GTX 560 Ti as PhysX, though the PhysX card is useless in this game). Aside from the buggy game at launch like backwards flying dragons and such, I've never had issues with my Nvidia GPUs.