Broadband problems with home network

Can you help, I have 10meg virgin broadband, a virgin modem into a planet FSD-803 ethernet switch wired to 2 pcs and sometimes my laptop, all with windows XP. Laptop has latest Norton PC,s have AVG.
Cannot get more than one computor at a time on broadband. When you try and get second comp on it will be connected at 100mbps ie on network but will not connect to internet seems to have have trouble when getting past default gateway. Anybody any ideas, Virgin are a waste of space and it is doing my head in Any help v/gratefully needed !

Are you running a DHCP server anywhere?

Hi
No I don,t
Is this necc, if so how do I

Thanks in anticipation

If you don't have a DHCP server on your network then you need to setup each device with an IP address and default gateway manually..

This is why its so much easier just to buy a wireless router/modem all in one device rather than trying to cobble things together as the all in one devices have a built in DHCP server and also handle NAT so that all your internal PC's get a private IP address set for them when the come onto the network and then the NAT enables them all to use the internet connection simultaneously.

These things are so cheap nowadays you can save so much hassle by getting one.