Noddy as in children's books? Well, ok. I'll try. No words over 3 syllables, no hyphens, no apostrophes, and less than 3,000 words. I took teacher's prep classes about 30 years ago and it's tough not being
See TV set top box. See if box is a router. If box is a router, there is little to do. Plug in your cables. The router will send an IP address to your computers. If the box has a label, you might tell us the model.
If TV set top box is just a modem, then you must make a decision. The best way it to buy a router. The router will do all the you need to share the box. It will also be a firewall to keep evil people like me out of your computer. A router is the right way to do this, but it will cost money.
You can save money by using your computer for sharing. ICS or proxy server softare will make your computer play like a router. I do not like this because you must make your computer run all the time.
You have not told us if you can use your set top box with only one computer. The internet must work with one before it can worth with a router. Do you have cable modem service? Is the service on? Did you tell the cable company you have a new MAC address? Do your cable people have written pages for setup? I think it is NTLWorld but I am not sure. See:the basic setup. You should try to make it work with one computer first. If you have no router, you should see if you have a firewall running on your XP. That will be the XP SP2 firewall.
Is that sufficiently noddy?