do grafics card die?

do they cause when i got my geforce 6600 1 year ago it worked really well like i could play the orange box maxed out(without filters) onn my 22" moniter. and now im getting lag on half life 2, still with high settings still but it on the lowest resolution in a window. also is there a difference with RGB and DVI?

 

Yes, graphics cards die. The GF6600 is an older model and I'm assuming you bought it used, but there could be many other reasons why you're getting lag. You should read this guide on system maintenance to make sure your PC is running optimally. You could also possibly have malware, a hard drive starting to fail, an overheating CPU/GPU, etc. By RGB are you referring to a std video connection? It's a 15pin VGA port and it looks like this:

http://upload.wikimedia.org/wikipedia/commons/thumb/3/30/DE15_Connector_Pinout.svg/300px-DE15_Connector_Pinout.svg.png

I see no reason why a game would run slower on VGA or DVI, either port would have the same performance.