REG_DWORD: These values use a 4 byte number as data, and are shown in hexadecimal format with the decimal equivalent in brackets next to that. Either format can be used to enter DWORD values. DWORD entries are one of the two most commonly edited value types, and are normally used for 'switch' values, meaning a value that is either off ('0') or on ('1'). When creating a new DWORD in REGEDIT, use 'DWORD value' with the 'new' command.

REG_SZ: Also known as a string value. These represent data as a string of characters. This string can be a word, a number, or the location of a file on your system's hard disk. The other most commonly edited value type.

REG_EXPAND_SZ: A string value that acts as a variable, where an application or input from a user can place a value.

REG_MULTI_SZ: A string value that contains multiple values or lists.

REG_BINARY: Holds values as binary data. Generally used for hardware information that is not intended to be accessed or changed by users.

The vast majority of registry editing tasks involve creating or editing REG_DWORD and REG_SZ values.

Editing the registry with REGEDIT

Now we are going to perform a simple registry edit which will place your Windows XP version number on the desktop in order to demonstrate the procedures needed to change the registry.

First, Double-click on HKEY_CURRENT_USER to expand this branch of the registry. Now Find the key 'Control Panel' and double click that. Finally, locate the subkey 'Desktop' and click it. You will see a number of values in the right-hand pane. Scroll down and highlight the 'PaintDesktopVersion' DWORD value. Double click the value to bring up the editing box.

Ensure that 'decimal' is selected as the base, and type 1 into the 'value data' box then click 'ok.'

Due to the nature of the registry, any changes you make here do not have to be saved. Some changes apply immediately; others are applied upon restarting the system. This also means that there is no 'cancel' button for undoing accidental changes, so make sure you keep careful note of the values you intend to edit.

If you do not wish to have your version number displayed on the desktop, reset the PaintDesktopVersion value to '0'. Otherwise, close REGEDIT. Once you restart the computer, the version number will be displayed in the bottom right hand corner of the desktop.

Many of the registry edits out there require the adding of new keys, subkeys and values. To do this within REGEDIT, simply right click the location where you wish to add the key or value, then select 'new' followed by the type of value or key name.