Hello
Usually I install the operating system on drive C and keeps programs' data files on drive D.
The problem is the My Documents special folder which is by default on drive C.
I found out that there is a simple way to move the My Documents folder to another location (with all the OS shortcut pointing it)
1. Double click My Computer.
2. Choose Desktop at the address bar
3. Right click My Documents -> Properties.
4. Use the Target tab page to select a different location.
I guess you can do it directly from your desktop if you haven't removed the My Documents icon.