command line - `cd` doesn't change directory in Windows 7

Possible Duplicate:
Using cd Command in Windows Command Line, Can’t Navigate to D:\
CMD cd to other drives except C:\ not working

I am working with cmd.exe on Windows 7 (as opposed to Powershell). I have 2 partitions on my drive, C contains the OS and installed programs, and D contains my data. I was trying to cd from C to D, but cmd wouldn't let me:

C:\>cd D:\

C:\>

However, when I type dir D:\, it will list the contents of D correctly. Why does it do this and how can I fix it? Powershell works fine so I can use that, but I would like to know what makes cmd misbehave.

Answer

You have to use just d: , not cd d:\

EDIT: it is also possible to use cd /d d: to change drives using cd