Frequently, your Windows PC may be slow; you may get various errors (such as runtime and JavaScript); or you may get crashes (either of a particular program, or of the entire operating system -- usually causing a "blue screen of death"). Problems with the Windows registry can cause many of these difficulties (which can range from annoyances to catastrophes); Windows registry problems can be fixed with a Windows registry cleaner.

What is the Windows registry? It is an internal database containing things like program locations, file locations, directory locations, and various other settings (like those set on the Control Panel). For Windows to start up a program to use or edit a particular (type of) file, it needs to know where to find that program, and it looks in the registry to find the program. To start up a program, Windows may need to locate certain files aside from the program itself -- usually files (e.g., DLLs) that are used by more than one program so are kept separately from individual programs. The program itself is likely to need to locate files for it to start up (such as settings and fonts) and may need directory locations (such as for where to put backup files); programs may also need such information to do certain operations after they start up. For all of these, Windows or the Windows program will look in the Windows registry.

Unfortunately, the Windows registry frequently gets corrupted when it is changed. When will it be changed? It is changed when programs are installed or deleted, when Windows updates/patches are done, when settings are changed, and when malware (adware, spyware, viruses, et cetera) infects your computer or is removed. The registry may simply have entries in it that are blank and no longer used (such as for a program that has been removed); these will slow down lookups into the registry, thus slowing your computer. The registry may, worse, have actual erroneous entries, pointing to programs or files that are misplaced, corrupted, or simply missing; these can cause errors (including crashes).

How can Windows registry problems be fixed? In general, the best way is by using -- on a regular basis, whenever problems happen, and whenever malware is removed -- a Windows registry cleaner. These programs look for blank or corrupted entries and fix them.