Normally if you bought your laptop with Windows 7 pre-installed ,there only was on partition (C drive).Fortunately,we can resize partition free in windows 7 and below steps will show you how to split C drive to 2 or more partitions for free.
1.Right click My Computer then click Manager
2.In the left pane,select Disk Management ,then right click C drive and click Shrink Volume…
3.The type the amount of MB disk space you want to shrink ,then click Shrink
4.Now you will see there is an unallocated free disk space,then you can right click it and select New Simple Volume then follow the instructions to create a D drive
Note:It is recommended to left enough space for C drive.