Try this. You'll have to give one another letter to free one up then give it the letter you want. My cd rom is x. Now it is out of the way of everything else.
To Change Drive Letters
Go to Start > Control Panel > Administrative Tools > Computer Management, Disk Management, then right-click the partition whose name you want to change (click in the white area just below the word "Volume") and select "change drive letter and paths."
From here you can add, remove or change drive letters and paths to the partition.