Go HERE and use the enter your service tag option. This will take you to the Drivers and download page. Next select your operating system. Once the operating system is selected scroll down to the network  listing. Click on it and it will give you the drivers for you particular system 
I recently got a Precision 6400. It was pre-loaded with XP 64 and everything was working alright until I decided to install Vista 64, it was a clean install by the way. Now if I try to connect to the internet, it says there aren't any networks going so I click diagnose problem and it says "this computer does not have a wireless network adapter installed and configured. So then, my questions: 1) Does anyone know how to fix the problem? 2) If it's driver related (which I'm predicting it is) can anyone tell me what drivers I would need. I literally just got it and I don't even know what make or model the network adapter is. 3) If noone knows the answers to the above, is it likely that reinstalling XP will fix the problem? Well, thankyou in advance if anyone can help me with this. Worth saying I have Windows 7 on order but it won't come for a month yet.
Connection Problems.