Update: You can get TuneUp Utilities 2008 for free! Click here .
TuneUp Utilities is a highly respected commercial-now-free software that helps maintain your computer. It can perform tasks such as registry cleanup/defrag and disk cleanup. It includes features that allow you to style your windows and control start up programs. There is also a ‘shredder’ and ‘undelete’ feature which allow you to securely delete files and recover files you already delete. TuneUp Utilities is recommended to the fullest. This is the description by the developer:
The new TuneUp Utilities 2007 will make Windows even faster, more comfortable and more secure than ever. All important aspects of system configuration, security, cleanup and maintenance can be accessed through a modern graphical interface: Configuring the system, making backups and performing maintenance can be easily carried out using the intuitive user interface – all easily done in one program at a single glance.
If you are still interested in TuneUp Utilities 2007, visit this  webpage. At that webpage you will find a registration code about half way down (it is 100% legit). Copy that registration code. Then download TuneUp Utilities 2007 by either clicking on the “Download Now” button you see on that same webpage that lists the registration code, or you can download TuneUp Utilities 2007 from here . Install TuneUp Utilities 2007 and paste in the registration code when you are prompted to do so.
Initially when I heard about free TuneUp Utilities 2007, I was not very interested because I already had WinUtilities  which was a giveaway from GOTD earlier. Then I decided what the heck and I tried it anyway. As far as I know, WinUtilities is a resale of TuneUp (however don’t quote me on that – I only read it somewhere). That being said the ‘core’ features of WinUtilities and TuneUp are pretty much the same – registry clean up, disk clean up, system optimization etc. But WinUtilities seems to have a few ‘extra’ features such as EXE password protect, autoshutdown computer, and file splitter. That being said TuneUp also has a feature called “RegistryDeFrag” which I cannot seem to find an equivalent in WinUtilities. Bottom line is that the programs are very similar in features. But in performance? They are different but equal.
The following are other commercial-now-free software that are similar to TuneUp Utilities 2007:
WinOptimizer 5 
Desktop Maestro 2