I cant partition less than 500gb on 1tb drive

Im trying to partition the drive but I cant make the C drive less than 500gb. I followed this guide How to Resize Disk Partition in Windows 7. How do i make it smaller. I wanted to make C for Win7 and extra, but not half the hard drive. Thanks

Use free Partition Wizard bootable CD to Resize the partition.

If it won't go small enough for you, use free Perfect Disk 10 trial version to defrag for compactness, then rightclick on partition to Offline Defrag>System Files.