Netgear WGT624 wireless router problems

I'm having problems with the Netgear WGT624 wireless router. it works fine as a wired router, but computers connected to it wirelessly cannot access the internet through it. The computers can get onto the admin settings page etc, but just not the internet. It seems very inconsistent too because it worked a few times before but after changing one setting on the router they could no longer get the internet through it. Sometimes it would just fix when trying to renew the IP address but usually it cant even do that. If i go into the command prompt and type "ipconfig /release" then "ipconfig /renew" it gets a new ip successfully, but if i "Repair" the connection using the network connections option in windows xp it says it was unable to renew the IP address. Would a firmware fix it? I haven't updated the firmware at all since i bought it because i've been afraid it would stop working like what i've heard about so many other people before. What should i do? :O