Posted 13 August 2010 - 11:52 AM
First of all, it sounds like your router is set to only hand out three DHCP addresses. You don't mention the router make and model, but there is usually a LAN page that includes the minimum and maximum addresses to be assigned. Make sure you have a few in there and that you do not use one of those addresses if you assign yourself one statically. I generally use (192.168.1 or your subnet).50 to .100 for DHCP assignable addresses, and any statics for servers, routers, and printers go in the .1 to .49 range and any static clients (desktops or laptops) in the .101 to .250 range.
Secondly, your DNS address is generally assigned by your ISP but you can almost always use the address of your router (most use DNSMasq to cache and service DNS requests) which is usually 192.168.1.1 or similar. There are also services like OpenDNS that can provide value-added DNS services, but they take a little more setting up to get the benefit.
Easiest fix is to correct the router config, next best is to set DNS address to the router address. The big problem with setting a static (particularly on a laptop) is that every time you move to a different network you will have to reconfigure.