The reason why shrink volume
You could need to create a new partition in Windows 7 to install dual-boot with Windows XP. The problem is when you try to shrink the system partition size, it will only allow you to shrink it by 100MB, but as a matter of fact on the system volume there is 50GB of available free space. Furthermore, you have defragged the volume, deleted all shadow copies, and ensured that no page files for this shrinking volume operation. You have been trying to use the built in Vista partitioning utility to shrink volume, but after that didn’t work.
How to shrink volume with Partition Assistant
Partition Assistant Standard Edition (FREEWARE) can well shrink system partition to meet your needs. The following is an instance to shrink volume the C: drive from 35.93GB to 20GB.
You can launch the Partition Assistant as administrator privilege. In order to shrink volume safely, we suggest you first close all other programs before launching the software.
In the above screen, after drag the double-headed arrow to the left, you will see the C: drive that has been shrunk.
When shrink volume C: to a proper size, please remember clicking the Apply (in the toolbar) or press Ctrl + Enter, then will popup the dialog box, you need to click the Proceed button to apply the operation to physical disk.
Now, you can create a new partition in the unallocated disk space (15.93GB) to install dual-boot with Windows XP. By the example, you will enjoy that Partition Assistant can completely make up for the shortage of "Shrink Volume" in Windows 7 Disk Management.
In summary, shrinking volume is a advanced repartition operation, you need to choose a appropriate software to do this. Professional Partition Assistant can shrink volume for Windows XP/Vista/Windows 7 etc.