How to create multiboot configuration with XP\Vista and Windows 7 on it? And most important question - how to do this correctly so not to have any kind of nightmares we get when system gets screwed?
First of all one should realize that Windows uses the same Boot Manager
for XP based or Vista based systems. When you install XP it installs Boot Manager
into MBR that controls OS load order. In case you install Vista to second partition without doing some precaution steps we're going to describe in this article then you risk installing boot files into existing system and OS files into second partition. Sure this will rewrite previous boot manager too so to make it handle both OSes. It means that boot order will be handled by one boot manager and in case of this Boot Manager
corruption you have a good chance to stay with none of your OSes loading. Good perspective, isn't it?
Let's imagine that we have a system with XP or Vista (in nearest future Windows 7) installed on it and you have a good feeling that you need one more OS. Just to look at it or use it for older programs (newer programs). What are the steps?
As an example we will take Paragon Partition Manager 10/11
product though other vendors do provide similar functionality too.
Create Recovery CD from interface of this Partition Manager.
Boot system from the created CD and get into interface where disks' layout is shown. It can be done this way - Insert CD into CD-ROM - restart machine - select Normal mode on first screen then follow to Partition Manager.
There right click on partition and select Hide.
Hide all partitions (drives) except the one you want to install new OS into.
Then eject Recovery CD from CD-ROM and insert the Windows Installation CD\DVD.
Run installation and point it to the partition left for this purpose exactly (not hidden)
Complete installation; install your drivers and software.
Boot from Recovery CD and proceed to disks layout window directly.
There unhide all hidden partitions and restart to Windows.
In Windows run Partition Manager - advanced options - Tools - select BM install Wizard. This will activate Boot Manager that allows selecting which OS to boot at post BIOS screen. One can bind the Boot Manager call to F key (this is called hidden mode) or get the OS selection screen each time system restarts (this one is Normal Mode). When hidden mode is selected the OS with 5 seconds (could be changed) timeout goes directly to last loaded OS.
Your configuration is ready. This very way of multiboot organization guarantees you that other systems will remain intact in case one of them gets screwed. Boot Manager will not boot from screwed system but all other must load just fine.
Other known vendors that provide similar functionality: Terabyte (BootIt NG), Acronis (OS Selector) or Linux.