Here are some possible thoughts about what you're trying to do.
One of your disk drive partitions is, apparently, for Linux. In that case you probably have a program called Grub that controls the boot order. The difficult part is whether or not the version of grub properly loads up Vista or Windows 7. Once you get the way you want it might be something like this:
First the Grub loader offers you the choice of loading Linux or loading the Windows system. You will want the Windows system to be first on the list. Next, you'll see another list that shows earlier version of Windows, Vista, and Windows 7. The earlier version of Windows should be first on the list. That will be XP.
So then, you probably will have to go in and edit the file for the Grub loader inside of the Linux OS. Then after that you have to go into the Windows 7 or Vista system, hard to tell which one would be, most likely the Windows 7. There you would again edit something so that the old operating system will come up as being the first. Windows XP is called the earlier version of Windows.
SRS Windows is concerned, you can use a program called BCDedit. As for the Linux system, I am not sure how you get it to load the Windows 7 boot loader. In fact, you may not be able to do that unless you update the boot loader. So you'll need to find somebody here in this forum that's a real expert on Linux and how do use the boot loader. I tried some time ago I had to give up. I just didn't understand anything about it.
now if you're not using the Linux system very often, you may just choose to edit the boot loader for Windows and make the Windows boot loader the default loader for the system. I believe there is a way that you can force the boot into Linux by using a floppy disk. Or use a boot CD and tell it to go into the operating system that's already on the disc. I recall there is some kind of a command in Linux region tell it that the root is on the hard drive and not on the CD-ROM.
Sorry I can't be of any more help. But there's other people here that can guide you through this. The question is what you really wanted to, and what you have on that disc now.
EDIT: You may want to download EasyBCD. They say it is the answer.
Here is a video that shows what it does:http://www.youtube.com/watch?v=zdjNfXZjRxs
