can’t ping LAN but can access Internet

Hi. I have something weird happening. I have a computer with ip address 192.168.1.154 and subnet mask 255.255.255.192. The gateway is 192.168.1.129. All the pc’s on the LAN can ping each other and the gateway except for this one.

Its a Compaq portable with XP Pro on it. I cannot ping anything on the LAN (not even the gateway). However, I can access the Internet and ping public ip’s on the Internet.

I thought it may be Norton Internet Security but I uninstalled it and still have the sameproblem. I can’t find any other firewall software installed. This happens when using the integrated nic and also when trying to use a pc card nic. Any ideas?