Download Partition Wizard Bootable CD
and burn it in a CD using ImgBurn
. Boot from the newly created Partition Wizard CD .... it will open all your partitions .
You cannot interchange the partition names . First rename D to any free letter, say T . Then Rename E to D , and finally rename T to E . Apply changes .
Now Shut down your computer . Open sata ports , and then join those again, in proper arrangement . Start your computer now . It should do the changes .
But Never Never touch your C drive, unless and untill you do have a complete system image backup .
The easiest way to get the proper arrangement is Clean Install Windows 7
Edit : Sorry Bill ! I am late with a harder process .