I must agree that the missing Gui is a little difficult, when all that you can see is this little orb turning around
Here's everything relevant I could find.
Vista computers may experience more fragmentation than WinXP-based systems because of all of the disk swapping that takes place. Consequently, it is important that Vista users defragment frequently to preserve their computers’ performance
Microsoft automatically schedules a defragmentation to occur every Wednesday at 1am
Manually defrag C: -a -v
The defragmentation engine itself is more powerful in Windows Vista and Windows Server 2008 than in earlier versions of Windows
If there is any free space at all, Defrag will make an attempt to defragment the volume. (ie does not require 15% Minimum like Xp did)
Why was the defrag progress indicator removed?
Part of the problem with the Windows XP defrag tool was that percent complete was not accurate or meaningful. Depending on the phase of defrag, 1% of progress could take from several seconds to minutes, which made the progress indicator highly unreliable. The difficulty here is that since defrag is a multi-pass process (multiple iterations of file defragmentation and free space consolidation) there is no way to accurately predict when defrag will complete since the number of loop iterations and how long each takes are highly dependent on the layout of the files on the volume, the level of file and free space fragmentation, and the other system activity. While I agree that having no progress is bad, misleading progress I believe is worse. Also, the idea behind the new automated defrag is that users will not have to think about it not worry about the progress it is making. With defrag running regularly, the system will be close to optimal levels of fragmentation, and subsequent defrag runs should not take long.
Turn off Vista Defrag: (Not Recommended)
1. Click Start.
2. Click OK to the UAC if it appears.
3. Click Control Panel.
4. Click OK to the UAC if it appears.
5. Click System and Maintenance.
6. Click OK to the UAC if it appears.
7. Under the Administrative Tools section at the bottom, click Defragment your hard drive.
8. Click OK to the UAC if it appears.
9. Click or unclick Run automatically (recommended) depending if you want this feature enabled or disabled.
10. Click OK to the UAC if it appears.
11. Click OK
12. Click OK to the UAC if it appears.