If you currently have only a C: partition of 446GB and want to make a D: and E: partition, then you go to Disk Management (right-click [My] Computer, Manage, Storage), right-click the C: drive and choose Shrink.  It will tell you how much it can shrink it - it likely won't be able to shrink it more than about half.  If you are ok setting up a D: and E: partition with a total of 200-250GB, then go for it.  If you want to allocate more space than it says it can give you, then you will need to either use a third-party utility to resize or reformat/reinstall to your specifications. Keep in mind, you can only have 4 primary partitions.  If what you are doing requires more than 4, then you must create the 4th one as an Extended Partition, then Logical Partitions within it.
i have bought dell xps l502x and i want to partition the hard disk how can i do that .can any body let me know the whole procedure???? further can any body tell me that there are two things listed under hard disk drives 1)os(c:) with 446gb 2)microsoft office click to run 2010(protected)(Q)   now i want to know what is this  "microsoft click to run 2010(protected)(Q)"  ????? 
hard disk partitioning