I need a motherboard that can use the same case

you can use any ATX mainboard into an ATX case, they are universal. Your cpu will only fit boards with the same cpu footprint so you need to know what socket your cpu is.. lga775 is most common now. I would advise a Gigabyte EP45-UD3LR board. Excellent board and well worth the outlay.. no issues with windows xp or vista and you can expand drives and ram as you wish..

If your computer case is ATX then find a motherboard that the form factor is ATX also so that it will fit in your casing.

That would be a Socket 478 Motherboard, they are very scarse now days i dont know of any shops which still sell them. You may find you will have to settle for a used board or maybe think about upgrading to a Socket 775 Motherboard and also replacing the CPU and Memory. Most Socket 775 boards nowdays will support most Pentium 4 CPUs and Duo & Quad core CPUs.