I have an HP ze4500 laptop and the motherboard is fried.... it won't power up.

Now,I understand desktop hardware... atx mobos need specific ram, cpu slot support and all, but I'm lost when it comes to laptops.

Do they all use the same form factor? .... e.g., what should I look for when crusing ebay for a new/used mobo? Does it have to be specifically built for the same manufacturer and product range?