I assume Windows as he talks about "drive d". This questions would be better suited in any Usenet group about Windows.
With Windows you are only able to setup a new partition if you have enough free space on your hard disk. Otherwise you will either have to repartition your drive and loose all your data or you can use a third party tool like Partition Magic from www.powerquest.com (highly recommended).
Regarding the dual boot system: which combinations of OS?