A Clean Registry cures a sluggish system

The Windows registry is a directory which stores settings and options for the operating system for Microsoft Windows 32-bit versions, 64-bit versions and Windows Mobile. It contains information and settings for all the hardware, operating system software, most non-operating system software, users, preferences of the PC, etc. Whenever a user makes changes to Control Panel settings, file associations, system policies, or most installed software, the changes are reflected and stored in the registry. The registry also provides a window into the operation of the kernel, exposing runtime information such as performance counters and currently active hardware. This use of registry mechanism is conceptually similar to the way that Sysfs and procfs expose runtime information through the file system (traditionally viewed as a place for permanent storage), though the information made available by each of them differs tremendously.

The Windows registry was introduced to tidy up the profusion of per-program INI files that had previously been used to store configuration settings for Windows programs. These files tended to be scattered all over the system, which made them difficult to track.

The introduction of the registry created a new problem. As more programs write to the registry, the database size grows. As it grows, system performance can begin to suffer. Uninstall programs and poorly written applications do not properly clean up after themselves. This compounds the problem.

There are two solutions to this problem. Reinstall Windows or install a registry cleaner.