Hi Omid Farhang,
Starting again on a positive note, my good friend,
So, but when to tackle such issues in Windows?
You should clean your Registry as part of troubleshooting a software problem.
The problem could be specifically with Windows,
or it could be a third party software application or game.
I recommend people therefore to crap clean before shutdown
and to use Secunia PSI to watch over the update status of third party software...
A Registry cleaner scans through the Windows Registry
and removes information that's no longer needed.
But when everything runs without problems and
you did not cause the problem yourself, leave your hands off of the registry....
Back up your registry at regular times is always a good option...
Also check your programs with Dependency Walker and dll checker...
As Windows and your other software operate,
they should automatically "clean up" after themselves.
But they don't always, and over time electronic residue and debris build up.
The Registry grows bloated.
If this gets bad enough,
it could start interfering with normal operation.
The Registry concept was introduced in Windows 95.
Part of the reason was to have one gigantic centralized place to store software information.
This made programming easier and helped Windows operate more efficiently.
Theoretically.
In practice, it's taken a while for Microsoft to get the Registry operating properly.
Some would argue there are still flaws in the Registry concept itself.
But usually, Windows XP machines are pretty Registry-stable.
If you think you may need to clean your Registry,
here are reasons and situations that could indicate it's time for Registry "hoovering":
A program uninstall had problems, and the software wasn't uninstalled properly.
After installing or uninstalling a program, Windows starts crashing or acting funny.
First try additional and specific uninstallers.....
You've installed and uninstalled lots (and lots) of software over the years,
and are noticing more and more errors when doing so.
You're running Windows ME, Windows 2000 or older software,
and are noticing problems like those above.
These versions of Windows were less efficient at Registry management.
Also read about the ScanReg and System Restore tools,
as both of them are programs allowing you to save "snapshots" of your registry at different times.
You can then reload old versions as needed to restore your system back to a (pre-problem) state.
Also SpywareBlaster can regularly take scanshots of the Registry.....
polonus