Triple Boot With Windows 7, Windows XP and Ubuntu Linux

Yes, you can have your operating systems on separate hard drives. Most of my experience is with Fedora but if I remember correctly, Ubuntu's installation is very similar. First install windows 7 and xp. Each will ask you for a destination and it can be a separate HD or different partitions. You could unplug the power supply to the drives you want XP and linux installed to then install 7 to the only HD. Unplug that and plug in the drive you want XP installed to. Plug in all your hard drives and install linux. You will be asked where you want it installed. Be sure you are able to correctly identify the disk (be it by manufacturer name, size, etc.). You probably already know that linux does not identify it's drives as windows does. Ubuntu will ask you where you want to install the boot loader. Here you have two choices. Use Grub to replace the MBR in windows. You will be asked to identify the default system to boot from. Or (and I found this to be easier) simply install linux to the remaining HD, ignoring the first too. Then at boot up press F8 (i think) to access bios and then select which drive you want to boot from.

I'm pretty sure there's only one way to do this, which is installing them.

I think that this is possible on one drive, however it depends on which drive. Multiple partitions will need to be set up. Check with your drive manufacturer that the drive you have can support that many boot volumes. You can probably find that info on their web site. There are also some complications. Windows 7/Vista store their boot info on the first partition on the boot drive. So you need to install Win7 first. Then, install XP, which does not have that limitation, AFAIK. I'm pretty sure it doesn't, though. There have been plenty of dual-boots with XP and Vista, and even some with Vista and 7, but they have the same kernel, so it's understandable. Finally, install Ubuntu, which has no limitation and can tolerate the smallest boot partition.

Another option is to use VMWare Player or Virtualbox to run any of these all at once or one at a time. This way...you don't need to worry about which OS to install first...you can share files between each OS (if you're running them all at the same time) and if you need to reload...just zip up the whole folder and use it again after reloading.

Why don't you dual boot XP and 7 then install Wubi on one of them?

https://wiki.ubuntu.com/WubiGuide

Partition using Ubuntu. SO install Ubuntu first.

It can be done very easily, but when you boot into the Windows partion, it's most likely going to ask you to check the disk every time, because when you put Ubuntu on there, it's a totally differnt file system.

I think you better install them on either VMWARE or virtual box. Because is easy to switch operating system on your desktop while on the other and get a different software to work with especially on Ubuntu . You will hardly be using any if you dual boot. I did that, and hardly used my xp. The best of dual boot is, you are able to recover files in case of virus or system error on one OS.