This is a brief tutorial for technical savvy people on Windows's Registry. This tutorial is based on Windows Vista with Service Pack 2.
First, read Wikipedia: Windows Registry.
The registry is a database that stores settings and options.
Note: The registry is not for casual user to mess with, even a backup copy of registry cannot easily restore the state before you screwed things up . I assume you are a programer or sys admin background.
To look at registry, launch the Registry Editor. Type 【❖ Win+r】 to launch the run dialog, then type “regedit”.
Before you do anything, do a backup. In Registry Editor, click on the Computer to highlight it, then pull menu 〖File ▸ Export〗. Give it a name like registry_20091025.reg, so you know the date it is backed up. This might take a minute or two. On my machine, the saved file size is 458 megabytes.
Registry data are called key and value pairs. The “key” is like folders. Key can contain other keys. The “value” is like files. A key can contain many other keys and values.
At the root level, there are the following keys. (Note: the “Computer” shown in Registry Edit root is not a key.)
| Name | Abbreviation |
|---|---|
| HKEY_CLASSES_ROOT | HKCR |
| HKEY_CURRENT_USER | HKCU |
| HKEY_LOCAL_MACHINE | HKLM |
| HKEY_USERS | HKU |
| HKEY_CURRENT_CONFIG |
Each of the above is called a “hive”.
A “value” has several possible types. Here is a list of possible types:
| Type Name | Explanation |
|---|---|
| REG_NONE | No type |
| REG_SZ | string |
| REG_EXPAND_SZ | expandable string. Values between % char are expanded as environment variables |
| REG_BINARY | Binary data |
| REG_DWORD/REG_DWORD_LITTLE_ENDIAN | A integer, ranging from 0 to 2^32-1, with byte order being little-endian. |
| REG_DWORD_BIG_ENDIAN | A integer, ranging from 0 to 2^32-1, with byte order being big-endian |
| REG_LINK | symbolic link (char set in UNICODE) |
| REG_MULTI_SZ | A is a array of strings |
| REG_RESOURCE_LIST | Resource list |
| REG_FULL_RESOURCE_DESCRIPTOR | Resource descriptor |
| REG_RESOURCE_REQUIREMENTS_LIST | Resource Requirements List |
| REG_QWORD/REG_QWORD_LITTLE_ENDIAN | A QWORD value, a 64-bit integer (either big- or little-endian, or unspecified) (Introduced in Windows 2000) |