Out with the old, in with the new, as the saying goes. Except when it comes to computer hardware, when properly maintained parts can enjoy a new life inside a home server or media centre. But for your main machine, you eventually have to face the upgrade monster, especially if your GPU vendor decides it doesn't want anything to do with your aging graphics card.
This is the case for NVIDIA, which recently announced that a bunch of GPUs from 2009 and earlier will no longer be support beyond "Release 340" of its GeForce drivers -- specifically version 343 onwards. The most recent GPUs on the list are the 200-series that came out around five years ago, as well as the 8800 GT that was a popular workhorse back in the day.
It's not like they'll suddenly stop working, just that the 340s will be the best drivers you can install for cards using these chips and NVIDIA won't be looking to include optimisations or bug fixes in future updates. I'm sure there will be configuration file hacks that'll get newer drivers running on older hardware, but this will likely only take you so far.
The current WHQL GeForce driver version is 335.23, so you have some time yet before an upgrade is in order. That said, if you're not playing cutting-edge games, you don't have a lot to worry about.