What are the most important secretes you know to make windows OS be so fast and stable , especially by using registry editor ?

You could turn off the unwanted services.For instance the server is being used for file sharing only you could turn off the other services which are not required.In this case the service which we would be more interested is "Server" Service.Again its just a small example.I am trying to highlight the point that service that are required should only be made available.This should make a difference. Also check the processes that are running and investigate.You may use utilities like procexplorer available in system internals website.

Avoid using any external software that claims to boost the system performance.

It is not advisable to edit registry options, turning off automatic start up of programs during login may help. Just run msconfig and try to minimize the auto start up programs and other services that you dont need, this helps saving computer memory which you can use only on programs that you are using.

Making changes in the registry may not be the right way to go, there could always be after-effects later on.

1. Procmon: A good tool that lets you know how much process each application would take, and then you could optimize accordingly.

2. Msconfig: Tool whose function is to optimize the applications that are running in the background. Disabling unwanted and certain3rd party applications would definitely speed up the processor.

3. Defragmentation: A tool that allocates broken blocks of data aligned together as a continuous single block, so accessing them would be faster rather than having pointers to the various blocks of data.

4. Free up space on your primary partition.

5. If you have limited RAM, increase your virtual (page) memory. Else increasing RAM also big boost.

6. Error checking : Looks for corrupt/bad sectors during restart and tries to fix them.

There are several3rd party applications that do help, but you got to ensure authenticity.

In many times registory editor is quite helpful for making your system fast when you are in hurry.... Although if you go to minimize your installed programs and disabling unwanted services by task manager then it is much better  because it will make your system more fast  and stable by utilizing your system cache memory effectively and also your system takes lower time to reboot.

tuneup utilities