I downloaded from CNET recently many things and one I need to say is that I don't regret testing out applications for my own laptop. Some are bugsy and some are just plain OK.
One of the things downloaded was the WISE Disk Cleaner Free 5.71 which is a freeware but if you upgrade, there will be some extras on top. It reminds me of the old Norton Speed Disk Doctor (SDD) which works fine with XP but does not have that feature for Vista or 7 but the GUI looks the same.. it will scan and check the system and recommend if it wants to defragment or optimise it.
However, it does not wipe or optimise the free slack space where in Norton it compacts the files so that the free space is all at the end of the drive. It also can't move the system files, MFT and stuff to priority level one so it's loaded upfront such as the registry files.. but I can't expect much from a free-shareware right.
Other than that..it's great tool if you prefer to see what is going on rather than just the status report of microsoft's defrag.
One GREAT feature is that it can CLEAN OFF all the unwanted files and junk that Disk Clean up will forget, like log files and such, so that is one of the strong points... so try Disk Cleaner Free out.
Download is swift at CNET since it's just 4MB only... a few mins off ADSL or Wireless Broadband and you are into it!