Here are the easy steps to follow:
- Hit the Vista Start Button.
- Right click on Computer and select Manage.
- If you happen to get an User Account Control[UAC] dialog now - just click Continue(Vista's Inbuilt protection has kicked in).
- On the left pane, expand the Storage category and click on Disk Management.
- Now, you'll find all the partitions of your computer listed out. Right click on the partition you'd like to modify(Lets say d:).
- Select the option Extend Volume or Shrink Volume(Extend - to increase the size or Shrink to reduce the size) of the selected partition.
That's it - you're done. You have now successfully resized your existing Windows Vista Partition.