I have been having this problem and been searching all day on the net for solution, to no avail. Tried a few of the methods that were mentioned by others. While it may work for others, the same trick doesn't seem to work for me.
Whenever I click on C or D drive in My Computer, it does not show in the same window. Instead it will show up in another window. My computer is running on XP. The setting in the options are set to the following: Folder Options > General > Open each folder in the same window. This was working all along till today. All other folders in My Computer such as Shared Documents and Admistrator's Document are opening in their own window as usual.
Could someone please provide me with answers if you did faced this problem before and how you managed to resolved the issue? Thanks in advance!