EASEUS is the best software to partition.
if you dont have it use the inbuild disk management utility.
http://emdadblog.blogspot.in/2010/07/how-to-create-partition-in-windows.html
I have copy pasted it
How to create Partition in Windows 7/Seven ?
It is easy to create partition in Windows 7/seven. You can create partition on windows 7/seven using disk management utility from manage option. I will show you how to create new partition in windows 7/seven in easy steps in this post.
To create partition using disk management option follow below steps :
1. Right click on my computer and click on manage option.
2. A new window will open. From here click on Disk Management.
3. From here right click on desired empty/Unallocated space and select Simple Volume.
4. A wizard will open, click next and set the value for the partition in MB
I havent tries this method. I used easeus. This should work though.