Hello. This is my first post this year and it has been a long time since I wrote my last post. I was so busy with school’s things though. 
Ok, so you guys want to multi-boot your operating system with from WV or W7 or even UNIX based OS? There are something you must understand before you do this.
* First, back up all important documents and data files. I assume you have 2 drives already, don’t you? Copy all to your data drives.
* Make sure your former OS backed up, like using restoration DVDs or maybe an installation piece of DVD
* At least have 1 XP installation CD (you will know it why you need it.)
* After you finished that, let’s do it
Here I practiced on my Vista to dual boot with 7. Oh yeah, I never try linux at all, I don’t understand it at all, haha.
But, the principle of dual booting is you must at least have two partitions for each OS, and got the installation DVD or installation ISO file of course. Same to multi-boot.
- Make New Partition
On XP, Vista and 7
- Right click on My Computer, locate Manage and click yes if UAC asks, or go to Control Panel > Administrative Tools > Computer Management.
- On left pane, expand Storage, click Disk Management. You’ll see an image representing your C drive. You’re going to need to shrink this partition so you can create a partition for other OS.
- Right-click the C partition and select Shrink Volume.
- Decide how much room you want to free up for the other OS partition (30Gb is enough, because all Windows systems are under 20Gb for fresh install.)
- Wait til it completes shrinking the volume (and it might take a while.)
- Now there will be one new unallocated logical drive. You’ll want this partition to be formatted NTFS.
On Linux, see this link
Formatting error: If you can’t format the partition on vista or 7, try to boot your XP bootable cd, format that unallocated partition, but when it start to install XP, eject your disc rom and reboot.
You ask, why use XP cd, why not 7’s or Vista’s? I have tried 7’s, but couldn’t format it! I don’t know with Vista’s, though.
- Verify Your Old System is OK
Boot your computer or laptop, and you will new if your system is OK. If it is okay, then you’re ready to move on. =)
- Boot Your New Installation DVD/USB OS
This is the easiest step I think. Even 7 years old kids can do it. Just click yes yes yes and yes if nothing wrong with your installer.
You probably want some anti-virus software for your new OS installation too. Look for Kaspersky or other AV softwares. Almost updated available AV now support for Windows 7 and Vista already.
Good luck and I hope you enjoy using your former OS with your new OS dual boot machine.