Windows 7 and Vista
The procedure to dual boot Windows 7 with Windows Vista is very similar to the procedure of dual booting Windows 7 with Windows XP.
I assume that you already have Windows Vista installed and want to install Windows 7 with it in a dual boot configuration.
Again, if you already have a free partition which can house Windows 7, you can skip to the Windows 7 installation part. Otherwise, you will first have to create a free partition.
You can use GParted again to do it. Boot from the GParted CD, click on the Windows Vista partition and select Resize / Move.
Use the slider to reduce the space in that partition by about 20-40 GB to install Windows 7, click on the Resize/Move button and click on Apply to execute the resize operation.
Now you can either keep this unallocated space as it is or create a new partition for Windows 7. If you keep the unallocated space, Windows 7 will automatically format it and create a partition.
To create a new partition in the newly free space, select the unallocated space and create a New NTFS partition of adequate size. Click on Add and Apply the changes.
Alternatively, if you don't want to use GParted, you can also use the built in disk management tool in Windows Vista.
Just run diskmgmt.msc to enter Disk Management.
Select your partition and right-click on it. Select Shrink Volume. It will show you the amount of free space that you can shrink the partition by. Enter the size of the new partition (unallocated space) to be created and click on Shrink.
Now, just reboot your PC, insert the Windows 7 DVD and boot from it. When it asks about the type of installation, select the Custom (Advanced) installation so that you can select the partition you install Windows 7 into.
Select either the unallocated space, or the NTFS partition if you created it, and click on Next. The Windows 7 installation will now proceed.
In a few minutes, after the installation is complete (Yes, Windows 7 takes much less time to install), it will automatically install a boot loader which will allow you to choose whether to boot into the newly installed Windows 7 or to boot into the old OS (Windows Vista). After the process is complete, you can modify the boot loader details easily. Just run MSCONFIG and select the BOOT tab. You can select the timeout before the default choice is booted into, the default choice, etc.
You can also use third party software like EasyBCD to setup the Boot loader using a graphical interface, which is easier to use. It also offers many more advanced options.