Depending on the graphics load being put on the system its overloading the CACHE and Video card memory. Using online video requires caching and streaming video. This is taxing your Nvidia card. If you have DVD drive in the unit try playing a DVD disk and not streaming from web. This will enable you to determine if its the video syste. You will get pixelation and poor performance if it is a video card issue. If you get steady performance with offline video you need to be suspect of the buffer over run error on the PC using web video. Counter to popular thought sometimes newer drivers are written to accomodate new hardware and have detrimental effects to older hardware. Thats why I advise only updating video drivers, etc if you are having issues. Try using the roll back feature for your video card to the previous driver. Also in Vista there is a system restore feature. If you can identify a day that your machien was functional you can revert the whole system to that date by going to Start, Accesories, System Tools, System Restore. It wont affect any personal files, just updated system files. Finally you indicated this was primarily from Netflix. Have you tried Hulu, You Tube, etc. They all stream at different rates and you may have mroe of an issue with the service than the product. If there are no issues with other video sites, or offline video, you may have a hardware failure eminent such as a bad mother board or memory failure. Run a Memory diagnostic. For most machines you can access this at boot up by pressing a fucntion key (f2, f3, etc)