How to resize Your Partition Size in Vista:

1. Go to Start
2. Right click My Computer
3. Select Manage
4. Expand "Storage" in the Computer management Console
5. Select Disk Management
6. Right click any of the available volumes or partitions in the right pane of the Disk Management Console
7. Select "Expand" to increase its size or "Shrink" to reduce its size
8. Enter the size (in MB) that you would like to modify the volume or partition to.
9. Click Expand or Shrink to activate the modification