How can i fix This Problem: Internet Says it's connected but it disconnects from anything using the internet?

ok Well. I just got a New video card and windows XP sp3 And every since that my internet Says Its Connected But then it disconnects me from anything that uses the internet. It use to be fine. It still lets me play And get online but randomly Disconnect me from anything that uses internet. Sometimes it would reconnect itself or sometimes i would have to Right Click>Repair it. When im playing a Full screen Game Such as Command and Conquer Renegade Online. It disconnects me but my internet connection says that it is connected. Im using Wireless Conection 3 W/ DSL. My router is Linksys and my modem is SpeedStream 5100. If you need any Other Information post what you need here and i will Be sure to Reply.