This might be a problem that troubles many users. Generally, some third party software can provide such features. However, now Windows Vista/Windows 7 enables you to make some certain degree of adjustments towards current partition sizes.
Lets check the How-to:
PreparationAn essential requirement of this operation is that your file system must be NTFS. FAT32 file system doesn't work.
Right click the drive -> Property -> on the General tab -> File System will display your file system.
If it is FAT32 system, it can be converted to NTFS.（Alert: Converting to NTFS will bring some trouble. For example, if there are two systems installed on the computer, and one of them is an earlier system like Windows 98 or Windows ME, then the older system will not be able to recognize NTFS's drive letter.）
- Start -> In Start Search, type cmd, -> and right click cmd in the result list at the top - >Click Run as administrator.
If you see a message saying Windows needs your permission to continue, don't be surprised. Just click continue to confirm.
- Type the following command, and press Enter to run it (x represents your drive letter, and it should be replaced with you specific drive letter).convert x: /fs:ntfs
- Wait for a few minutes, and don't close the window until you see the confirm message.
Cut a part of the current partition to be a new one
- Begin -> Right click Computer -> Manage.
- Locate Disk Management under Store on the left, and click to select Disk Management.
- Right click the partition you want to cut, and choose Shrink Volume.
- Tune a size on the right of Enter the amount of space to shrink. The value is the maximum value allowed by default, then press Shrink. (No matter how much free space is left, the space released won't be over half the size of the current partition).
- You will see part of the space has been released. Then you can create a new partition in this space.
- Right click the blank space -> New Simple Volume.
Add the undistributed space to the current partitionHere's another tip for you - if there's unassigned space following immediately after a drive letter in the Disk Manager, then this space can be merged into that drive letter:
- Right click the partition you want to extend (this partition must have unassigned space following immediately after it), and press Extend Volume.
- Then tune a size for Select the amount of space. The value is the maximum value allowed by default.
What if I come across with other issues during usage?Relax, we have a post specially created for this article in Microsoft Community Forum，in oder for convenient discussion. If there's any problem, you can reply in the post.
If this cannot resolve your issue, you can browse the Forum for good solutions.