Ping success but no intenet access?!?

Alright here is my problem I have two computers hooked together via a wireless router. one computer is hardwired to the router and the other is wireless.

here are the computer specs:

Pauls Computer
Windows 2000 Server
256 Mb SD100 RAM
1 Ghz Pentium 3
hard wired to the router via a Linksys network card

the other:

Davids Computer
Windows XP Home SP2
512 MB DDR Ram
Athlon 2600+
hooked up wirelessly via a linksys wireless network card.

alright, now that that have been done. here is my problem. I have the computer hooked up in this network Pauls computer can access the internet (cable broadband via RoadRunner) without a problem, in fact its never had a problem and was hooked directly to the cable modem prior to the network being set up. Davids computer, however, cannot access the internet, in fact it wouldn't automatically get an ip address via DHCP.

After a bit of tweaking and contacting Linksys I figured out the TCP/IP stack was a bit messed up. So following someonline tutorials I uninstalled the TCP/IP protocol and then reinstalled it from windows/inf. After i rebooted the computer and checked the wireless connection and figured out that it had finally seen the DHCP server and automatically recieved an IP address. using the command line i pinged Pauls computer and then the Router. Successs. Surfing through the My Network Places on Davids computer I could access Pauls computer and vice versa. All seemed to be working. Now here is where it baffles me.

I can ping any website with Davids computer with an 100% success rate. (i.e. i type "ping yahoo.com", and it works) and I can access Pauls Hard Drive and CD-ROMS through the network, but Internet Explorer, MSN messenger or just about any other program that requires internet will not work. In fact the only program that I know can access the internet is Norton Live Update. Im at a total loss. Any help?

~psiko

alright, here is what has happened...after messing with Yahoo (for some reason someone set it to log into a proxy server...) i got Yahoo to connect to the net and I can, on Davids computer, chat via yahoo. but thats it!! MSN Messenger, IE, or anything else cannot access the net...i thinking it was a Microsoft error tried Mozilla Firefox and AOL messenger....neither worked..so i have no idea...also the Launchcast radio on Yahoo didnt work either....could it be a HTTP error on my computer?!? i have no idea.

thanks in advance

~psiko

alright, what was going on is even though i disabled the Norton Firewall, it was running in the backriound and was blocking all HTTP and FTP requests going in and out of the computer...dont ask me why...so i just manually ended the process and *poof* the internet (not just yahoo) was working. oh well.

~psiko