Before creating new partitions on your hard drive, you should defragment the drive so that all data is stored at the beginning of the existing partition. Here is how to do it:
Start up Windows.
First, backup your files to CD-ROM, DVD, or an external hard drive. Also remember to backup your Internet link collection (Favourites) and your e-mails. If your data is encrypted, it is advisable to decrypt it before backing it up. This protects you from data loss because modifying hard drive partitions always carries the risk of data loss.
Next, start the Disk Defragmenter program under Windows. The program is located at "Start | All Programs | Utilities | System Programs | Disk Defragmenter". Select hard drive c:\ and click the "Check" button.
Click the "Defragment" button. Depending on the size of the partition and the amount of data on it, this process can take a long time (over an hour). If you have very large amounts of data, you can speed up this process drastically by deleting your files after you have backed them up (see the previous item) and restoring them once you are done with the modifications. In this case, please make sure beforehand that your backup is readable, otherwise there will be wailing and gnashing of teeth.
Click the "Close" button.
There is now space on the harddisk for additional partitions.