Running Windows 7 Profesional SP1 64bit, I have an SSD system drive at C: and a hard drive installed as D:. No firewall or a/v software running on the system. Logged in as an admin. When I click the shortcut at Accessories > System Tools > Disk Defragmenter, nothing happens. Same thing if I click 'Defragment now...' from D: drive properties > Tools. Shouldn't I see some type of user dialog box? The program linked to is called dfrgui.exe, so I expect there should be some kind of GUI.