WINDOWS
Registry
Mr.
S. Mani, IV year CSE, P.E.C.
Disclaimer!
Did
you know that even Microsoft does not give technical support for the Windows95
registry or the registry
editor called regedit.exe? You have to use it at your own risk! Microsoft
even claims that you can crash your system by editing the registry. But
before you get to edit the registry it is safe to make back up copies of
the registry files.
What is Windows Registry?
Registry can be called as a storehouse of important information
of Windows. Some of the interesting things that
can be done using the registry are changing name of the registered user
and his company, the icon file for My Computer, the name of Recycle Bin,
and even changing the dates that certain shareware are installed.But first,
the Backup!
Windows registry is stored in two files in the \WINDOWS directory of your
system. The files are
SYSTEM.DAT , USER.DAT. Every time Windows successfully boots the system,
these files are copied to SYSTEM.DA0 and USER.DA0. Thus you already have
a Backup in your system. Apart from this, there is a file called SYSTEM.1ST
this file is the registry file created during the first boot after installation
of Windows95. Inspite of these backups it is strongly recommended that
you make some of backups of these files as SYSBAK.DAT, USERBAK.DAT etc.
You can use Windows explorer to copy this file, or boot the system in Dos
prompt and type the following:
>ATTRIB -S -H -R SYSTEM.DAT
> COPY SYSTEM.DAT SYSBAK.DAT
> ATTRIB +S +H +R SYSTEM.DAT
Repeat the same for USER.DAT. If you are not confident yet, make some more
backups and store them
in floppies as well. In case you have a problem, you can always replace
the registry by your backup files. Boot in DOS mode, simply change the
attributes and delete the files SYSTEM.DAT & USER.DAT, now rename your
back up files as SYSTEM.DAT & USER.DAT and set the attributes to SHR.
What exactly is the Windows Registry?
The Registry is a central database that is created by Windows 95
during installation. The entries
in that database consist of the hardware, software, users, and preference
data for a single PC, or any PC on a network. Whenever the user makes changes
to the Control Panel settings, File Associations, System Policies, or installed
software, the changes are reflected in the Registry. These Registry settings
can be viewed with the Registry Editor (REGEDIT.EXE), which is installed
into the Windows folder when Windows 95 is installed from CD-ROM. Regedit
cannot be accessed through the start menu. The only way is to run it from
the run dialog box from the start menu. You can always create your own
shortcut to Regedit by dragging it from the Windows folder to the desktop
using the right mouse button.
Windows Registry Architecture:
Let’s get into Regedit and explore the architecture of the registry.
Click on start, click on Run,
type Regedit and press Enter. The Regedit window opens up. Maximize the
windows to view the contents fully. On the left pane you will have six
keys (folders) in My Computer. Each key has a set of values. On the right
pane, you can see that each value has a Name, Value and the type of value
(shown as icon beside the name). The type of data can be string, binary
or Dword. A binary value is an array of bytes and a Dword is a hexa-decimal
number with 8 digits.
Let’s see what the six Hkey_ handles are:
Hkey_Local_Machine:Contains computer specific information about
the type of hardware, software, and other preferences on a given PC. This
information is used for all users who log onto this computer. This can
be called as some sort of a super-set over other keys.
Hkey_Current_Config:This Key points to a branch of the Key Hkey_Local_Machine
\Config that contains information about the current hardware configuration.
Hkey_Dyn_Data:This Key points to a branch of Hkey_Local_Machine
that contains various bits of information regarding the System's Plug and
Play configuration. This information is DYNAMIC, meaning that it may change
as devices are added to or removed from the computer. I strictly recommend
you not to touch this part of the registry.
Hkey_Classes_Root:This Key points to a branch of Hkey_Local_Machine
that describes certain software settings. This Key contains essential information
about OLE and drag and drop operations, shortcuts, and core aspects of
the Windows 95 GUI.
Hkey_Users:This Key contains information about the users that
log onto the computer. Both generic and user- specific information is used,
and each user who uses the system has a Subkey.
Hkey_Current_User:This Key points to a branch of Hkey_Users
for the user who is currently logged onto the system.
You can close the Regedit window for now.
Getting Control Panel to Start menu
The usual way for going to control panel is Start à Settings à
Control Panel. Even after that you had to
double click on an icon and wait for the property window to open up. I
am going to show you an easy way and an easier way to do this.
The aim of the easy way is to create a shortcut to Control Panel in the
Start menu. Right click on Start
button and click on open. Double click on My Computer. Drag the Control
Panel icon from My Computer into the Start Menu window. Close both the
windows and click on Start. You will see an icon named Control Panel (
or shortcut to Control Panel). Click on it and the Control Panel window
opens up. Wasn’t that an easy way to get to Control Panel? Now let’s try
the easier way. But first you have to delete the Control Panel shortcut
you just created. Right click on Start and choose open. Then drag the Control
Panel icon from the Start Menu window to the Recycle Bin. Don’t close the
Start Menu window yet.
From Start Menu window’s menu bar, click on file, new and folder. A new
folder will be created. If you
are an expert in Windows you might do that using the right-click. Now rename
the new folder. To do that choose the new folder (click on it) and click
file, rename from the menu. Rename the folder as the new name given below:Control
Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}
Note that the 0 represents zero and not the Capital Letter O. Once you
have done that, close the window
and click on start. The Control Panel is there in the start menu, but with
a difference. This control panel is a cascading menu (it has got a submenu).
Place your cursor over Control Panel and hold your breath. The components
of Control Panel are all there. That was definitely the easiest way to
go to Control Panel components.
So what’s the trick in it? The trick is in the number 21EC How do you find
that number. That is where
registry comes into the picture. Make sure you have taken Back-ups of SYSTEM.DAT
and USER.DAT. Start Regedit. From the menu, choose Edit and Find. In the
find dialog box, type control panel and press return. The value Control
Panel will be found in a key called {21EC This is a Class ID for Control
Panel. So we are actually creating a pointer for the Control Panel using
the Class ID. Close the Regedit window. If you’re still not flattered try
the next one.
Changing the registered user’s name & company:
Almost all computers which were bought from assemblers will have a pirated
version of Window 95
registered to the name of xxx, or xyz or Mr. ABC or something similar.
I bet you would like to change that to your name. To view the registered
user information, right click on My Computer and choose properties. The
window will have the words "Registered to xxx" or something similar. Let’s
change that. Start Regedit (Make sure you have taken the back-ups copies
of the registry files). Go to the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
and click on Current version. Here you will see the values RegisteredOwner
and RegisteredOrganization. Double click on these and change the value
to your name and your Organization’s name. Close Regedit. Now see the properties
for My Computer. Is it registered to your name? Note that this license
holds good only for Windows and the accessories that came with it. Also
try the Help About in programs like Notepad, Calculator etc. They will
be registered to your name. But try this with any of the Office applications
like Word or Excel. They will still be registered to the old xxx name or
whatever. Apparently Office writes the licensing information somewhere
else which I have not found out yet! If someone out there knows how to
change the registered user for Office, please teach me.
Changing the name of Recycle Bin:
Have you ever tried to rename the Recycle Bin? If you right click on the
Recycle Bin, you will find
that there is no option for renaming the Recycle Bin. But this is not impossible.
You can do it with registry. The class ID for Recycle Bin is: {645FF040-5081-101B-9F08-00AA002F954E}
This key can be found in: HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\
Now double click on default and type a new name such as Kuppa Thotti or
Trashcan or anything else.
Close Regedit. Click on Recycle Bin and press F5. This will refresh the
icon and the new name will appear. You can also use the class ID to put
Recycle Bin in your Start menu. Follow the same procedure as for Control
Panel.
That is not all! You
can do a lot of things with the registry. Try hacking. Use the Regedit
to view
the registry, but be very sure if you want to change any value. Make backups
before you change any value.
Happy Hacking!
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Created by S.MANICANDAN and S.KARHTIK
( III year CSE, 1996 - 2000 batch)
Last Updated Date : 15th September 1998.