Can I offer you an alternative, friend, (I hope...) before
you "just do it?"
Buy a second hard-disk for your computer. Most systems have two
IDE-controllers on-board, thus the ability to run four
devices total, and they normally only use two: "the" hard disk and a CD-ROM. That gives you the ability to add two new drives. (And that's excluding any external stuff like FireWire or USB-2.0 that you might also have...)
Okay, then ... for maybe a hundred-bucks you can get, at any computer or electronics store, a spiffy new hard-disk with a mounting kit and a longer cable. Installation is straightforward. And with it, now
you have a flexible, versatile choice.
What you'll do is this: install Linux onto that
drive, and select that
drive, in your BIOS, as "the boot drive." You leave Windows-XP alone
, making absolutely no changes to it. (Obviously, Windows will notice that a new drive has been installed, and that it is partitioned, and that it has no support for any of those partitions .. so it will ignore the drive.)
See, this is much better than "repartitioning." You don't have to change anything
about the drive you have, and the OS you have. You don't have to fiddle with installation-procedures to make sure that either OS doesn't get accidentally wiped-out. Each one is able to use its own standard installation and upgrade and reinstallation procedures, without modification.
Since "the problems arise when the two cousins must share the same house," you give each of them a separate house to live in. (On my main machine, I do
have a total of three drives, the third being primarily used for backup and as amazingly-useful "attic space.") Now, if one of the OSes goes
... you can reboot into the other in minutes while you
... in short, you can keep going.
You can now... select the Windows drive as the boot-drive and boot it; or select the Linux drive and boot it.
And you can flip back-and-forth between them anytime you like, always certain that Windows-XP is still there if/when you need it. (Obviously, as you will see, there are ways to put up a boot-menu that will choose between either, and in due time you can do that, but meanwhile, "this will work.")
And, you may, for many years to come, continue to use Windows! If there's a great program that you want to run or need to run, and it works best on Windows, then "you got it." (Why constantly
be confronted with the learning-curve, "just to get anything
done?") For most things, you may well use Linux. Or, you may use Linux primarily as "a learning experience" and continue to do most things in Windows. My point is, now, the choice is yours.
You don't have to throw out the baby with the bathwater.