1) The recovery disks that come with prebuilt computers are specific to that hardware - they are not full Windows installs and lack drivers for other systems. You will almost certainly need a full XP distro disk.
2) If each of those machines is pre-built, they came with an OEM license that can't be transferred to another computer. If one of them is homebuilt and retired from service, and you installed a retail Windows license, you will be able to use that license. But it sounds like you don't have one, or you would have the full media.
3) The A70 that is wiped - what OS did it come with? You may be able to install that version of the OS using the product key on the case sticker - if there is one.
4) Otherwise, you are going...