After installing Windows 7 in a separate partition as a dual boot option with Windows Vista in another partition you may notice some problem, it may happen that you won’t be able to see the partition where Windows Vista is located. This is due to a little glitch which doesn’t assign the letter to the partition in Windows 7. Here is the easy trick to fix it.

1. Click Start.
2. In the Search Box, type diskmgmt.msc and hit Enter.
3. You should now see the Disk Management utility, and inside it the Windows Vista partition without any assigned letter.

4. Right-click on the Vista partition and from the menu select Change Drive Letter and Paths.
5. Press Add.
6. Select the radio button Assign the following drive letter.
7. Select your favorite letter.
8. Done!