Learning about Windows Registry - part 1

Hi, as you know that almost all Windows configuration is saved in registry files. They save it in two files that can find it in windows folder (usually in C:\Windows). They are system.dat and user.dat and globally system.dat is containing your computer machine information and user.dat is containing user configuration data.
You may display and change registry value with Registry Editor utility, you can find it in windows folder too. There are two ways to open Registry Editor, first find the regedit.exe and double click it or click Start - Run menu then type regedit inside its textbox.
And globally, registry has 6 handle keys (some people call root keys) :
1. HKEY_CLASSES_ROOT : this handle keys is containing file associations and this part is identically with HKEY_LOCAL_MACHINE\SOFTWARE\Classes.
2. HKEY_CURRENT_USER : this handle keys is containing every user settings.
3. HKEY_LOCAL_MACHINE : this handle keys is containing computer settings globally and all infomation that linked with hardware & software are saved here.
4. HKEY_USER : this handle is containing specific user configuration, including wallpaper, resolution every user in your computer. HKEY_CURRENT_USER also linked here to take some configuration value.
5. HKEY_CURRENT_CONFIG : this handle key is containing hardware profil configuration although you don't make some hardware profile, this handle key will save the default value.
6. HKEY_DYN_DATA : this part saves the dynamic information that need updated regularly by Windows. For example when you plug new hardware and plug and play progress is running so Windows will write temporary configuration at here first. (I found that's not every computer have this computer, including mine :D )
OK, I plan write the second part for next week.