From: jeremiah wright on

Free registry cleaners can help you to get rid of all those pesky
system errors and crashes and also improve overall pc performance.
Problems with the windows registry is a common cause for Windows
errors, crashes and lack of performance. To resolve these issues you
can either format your hard disk and reinstall the operating system
and all the programs you installed over time or run registry cleaner
software.
The registry is a file in which the Windows operating system is
storing crucial information about your computer. It stores information
about your hardware, software and settings you made to this software
and hardware. This data is crucial to keep your pc running smoothly. A
common complaint of users is that their pc is getting slower after
some time. This is because invalid entries exists in their registry
due to software which is no longer used or software which was not
properly removed. As you keep on installing and uninstalling programs
the register will get bigger and it will take windows longer to load
or cause problems because it cannot find certain entries....

Registry Repair: http://groups.google.com/group/regrepairsbv