I had the same problem. I found this and it fixed it :D
A. According to Microsoft, this behavior can occur when you open the Edit File Type dialog box for the Drive or File Folder registered file types.
For example, say you were trying to add the Print Directory feature to a folder in XP. This change could cause the problem you are describing.
Microsoft acknowledges that this is a problem in Knowledge Base article #321379 and offers the following fix:
1. Start Registry Editor (Regedt32.exe).
2. Locate and then click the Default value under the following keys in the registry if this problem occurs with folders:
If this problem occurs with drives:
3. Click Modify on the Edit menu.
4. Type none in the Value data box, and then click OK.
5. Quit Registry Editor.