SASANK@TECHNOMANIA

I don't expect the average home PC owner to be involved in manual Registry editing but there is no reason why advanced PC users should shy away from editing the Registry directly, provided that they follow the iron-clad rule of always backing up first. It is also advisable to restrict direct Registry editing to small changes. If more extensive changes are involved, a script or an editing interface like TweakUI or the Group Policy Editor is a preferable method for making edits. Many useful Registry edits consist of changing one or two values and are easily reversed.

Accessing the Registry Editor (Regedit)

The Registry Editor (also called regedit) is not listed in the Start menu or in All Programs. The utility is a single file regedit.exe and is located in the Windows folder on XP systems. It is accessed by using the Run line. Enter "regedit" and the utility will open. In Vista the utility is opened by entering "regedit.exe" in the Start Search line The Run line can also be used in Vista (but is no longer necessarily on the Start menu). As to be expected, an administrator account is required.

Regedit is a two-pane interface with keys in the left pane (key pane) and value names with the corresponding data in the right pane (value pane). The setup is not unlike Windows Explorer with keys analogous to folders and values analogous to files. (The basics of Registry structure are discussed on another page.) An example is shown in the figure below.

Figure 1, Registry Editor (Regedit)

Also listed in the right or value pane is the type of data contained in a value. There are a number of formats that data can take and the usual ones that most PC users will encounter are given in Table I. I have omitted the more esoteric types. The three listed in the table constitute the vast majority of all Registry entries. Other data types are described at this Microsoft link.

Table I. Common Registry data types

Data type	Description
REG_BINARY	Binary data . Usually in hexadecimal notation. An example is 0xA8
REG_DWORD	Double word (32 bits). Can be edited in either hexadecimal or decimal
REG_SZ	A string. Figure 1 shows examples in the right pane.

Menus in Registry Editor

Regedit has some of the same menus that are so familiar throughout Windows. These can be seen near the top of Figure 1. Shown below are what two commonly used menus look like.

Figure 2. File menu	Figure 3. Edit menu

The File menu has the functions "Import" and "Export" that involve backup and restore. These are discussed on another page.

As you would expect, the "Edit" menu is where commands are located for making changes to the Registry. Keys and values can be deleted, added, or renamed. (Permission settings on keys can also be edited but that is an advanced subject beyond our scope.) Another two very useful functions are "Find..." and "Find Next". The Registry has thousands of keys and these search functions are very necessary. Unfortunately, the search function cannot find binary values or REG_DWORD entries. It searches key names, value names, and string data.

The bottom of he window for Regedit shows the path of the currently highlighted key as can be seen in Figure 1. The Edit menu also contains a useful entry "Copy Key Name" that sends the path of the key to the clipboard, Since path names can be quite long, this can be very useful.

Another menu that can be quite useful is "Favorites". If you find that there are is a certain key that you modify often, this key can be added to the "Favorites' list for easy access. The example of a "Favorites" menu shown on the right contains three favorites. Note the names have been chosen by this user and can be anything that is a convenient reminder. They actually refer to specific Registry keys, which can have very long path names.

Editing Registry Keys and Values

There are many useful adjustments to the Windows configuration or behavior that can be made by simple editing of the Registry. Unless you are a trained IT professional, you should probably limit Registry editing to one or two values at a time. I will limit this discussion to this type of straightforward scenario.

The first step in editing is always to back up the Registry. Also, back up the key you are working on. If you are a very careful worker, backing up just the key where editing is to be done may suffice but make a system restore point first anyway. To back up a key, open Regedit and highlight the key. Open the "file" menu and click "Export". For most cases. you will choose to export as a registration or REG file. This is a text file with extension .reg that is a copy of the highlighted Registry key. Save it to someplace safe. To restore a key with a REG file, right-click it and choose "Merge". On many machines the default left double-click on a REG file will also create a merge. I prefer to change the double-click action to "Edit" so that accidental mergers do not happen. Notice that I use the word "merge". Reg files do not replace keys but add to them, something to keep in mind. Anything extra that you may have added is not deleted. Some experienced PC users prefer to do any actual editing in the exported REG file and then to merge the edited file. This prevents accidentally doing something to the wrong key. Keep in mind that Regedit has no "undo" function. What's done is done.

If you are editing an entire key, you are very likely deleting it. (Careful! Back it up.) If you are making a number of changes, I suggest using a REG file and not editing in the Registry itself. I repeat, even power users should probably stick with editing one or two values. To delete a highlighted key, choose "Delete" from the "Edit" menu. Note that there is no recycle bin for deleted Registry keys or values. Deleted means gone to the great bit-bucket in the sky.

For the most part, direct Registry editing means changing a value. Highlight the value in question in the right-pane of Regedit. Then choose "Modify" from the "Edit" menu or right-click the value and choose "Modify" from the context menu. For strings, a box like the one shown on the right will open .As a specific example, consider the last value in the right-pane of Figure 1. The time that the system waits for a service to close at Shutdown is controlled by the entry for the value, WaitToKillServiceTimeout. The value is in milliseconds and the default is 20000 ( 20 seconds). To make things close up more quickly, you could change the value to 10000 (10 seconds). Or you might need to make it longer for certain systems. Enter the desired string in the line "Value data" and click OK.

A great many Registry values are strings but another type of data that is common is the "dword". A slightly different box will appear if you are editing a REG_DWORD value. The figure on the left shows the appropriate box. Note that when entering a DWORD value, you need to specify the base for the number. Be careful to be sure that you have chosen correctly between hexadecimal and decimal. You can enter either but the number that you enter must correspond to the correct value for the chosen base. In the example here the decimal number "96" would have to be "60" if hexadecimal were picked for the base.