I have a problem here ! WinXp on new Laptops

Hi All

I bought new Toshiba and Acer Laptop the problem is i want windows xp on both systems but when i try Xp says

Setup did not find any hard disk

There is no problem in installing Vista.

Some systems through bios we can disable sata then we can install xp, but i did’nt find something in bios, so the Question is how to install Xp.