Upgrading an Operating System and the follow-up Things to do

Upgrading an Operating System is not much of a task but one should always remember to make a back-up of all data before initializing the installtion process to be on the safer side. This will save a lot of careless blunders playing spoilsport to the operating system upgrade party. For starters, the upgradation process starts automatically by itself once the ‘Upgrade CD’ has been inserted into the CDROM. The next step is to choose ‘Upgrade’ option and not the ‘Fresh Install’ when prompted. There will be a prompt to upgrade and it will also ask which ‘File System’ to choose from. At this point, remember that using the same file system is always a safer option instead of taking the option of a new file system. This is the most valid way for upgrading an operating system.
The upgrade process does not take too long and after the operating system has been completed, the first thing to do should be to do a quick check on all the applications and see if they work. Reinstall them if they fail to respond or work. Any other complications with it can be resolved by checking up on the operating system vendor's website. One should also do a quick check on the hardware devices and figure out if they function properly. In the event of any hardware device failing to function after the upgrade on the operating system, then immediately the right driver should be deployed for the hardware. This support is also available on the manufacturer's website. A user can always get back to it for further reference.

Windows 7 registry: Understanding the usability of Root Keys

The Registry may be a dangerous tool, but you can mitigate that danger somewhat by becoming familiar with the layout of the Registry and what it various bits and parts are used for. This will help you avoid sensitive areas and stick to those Registry neighborhoods where it's safe to poke around. The next few sections introduce you to the major parts of the Registry.


Getting to Know the Registry's Root Keys

The root keys are your Registry starting points, so you need to become familiar with what kinds of data each key holds. The next few sections summarize the contents of each key.

HKEY_CLASSES_ROOT

HKEY_CLASSES_ROOT—usually abbreviated as HKCR—contains data related to file extensions and their associated programs, the objects that exist in the Windows 7 system, as well as applications and their automation information. There are also keys related to shortcuts and other interface features.

The top part of this key contains subkeys for various file extensions. You see .bmp for bitmap (Paint) files, .txt for text (Notepad) files, and so on. In each of these subkeys, the Default setting tells you the name of the registered file type associated with the extension. (I discussed file types in more detail in Chapter 3, "Customizing the File System.") For example, the .txt extension is associated with the txtfile file type.

See "Understanding File Types,"

These registered file types appear as subkeys later in the HKEY_CLASSES_ROOT branch, and the Registry keeps track of various settings for each registered file type. In particular, the shell subkey tells you the actions associated with this file type. For example, in the shell\open\command subkey, the Default setting shows the path for the executable file that opens. Figure 12.3 shows this subkey for the txtfile file type.
Figure 12.3

Figure 12.3 The registered file type subkeys specify various settings associated with each file type, including its defined actions.

HKEY_CLASSES_ROOT is actually a copy (or an alias, as these copied keys are called) of the following HKEY_LOCAL_MACHINE key:

HKEY_LOCAL_MACHINE\Software\Classes

The Registry creates an alias for HKEY_CLASSES_ROOT to make these keys easier for applications to access and to enhance compatibility with legacy programs.


HKEY_CURRENT_USER

HKEY_CURRENT_USER—usually abbreviated as HKCU—contains data that applies to the user that's currently logged on. It contains user-specific settings for Control Panel options, network connections, applications, and more. Note that if a user has group policies set on his account, his settings are stored in the HKEY_USERS\sid subkey (where sid is the user's security ID). When that user logs on, these settings are copied to HKEY_CURRENT_USER. For all other users, HKEY_CURRENT_USER is built from the user's profile file, ntuser.dat (located in %UserProfile%).


To know each users SID's, open the following Registry key:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList\

Here you'll find a list of SIDs. The ones that begin S-1-5-21 are the user SIDs. Highlight one of these SIDs and then examine the ProfileImagePath setting, which will be of the form %SystemDrive%\Users\user, where user is the username associated with the SID.

Some of the most significant HKEY_CURRENT_USER subkeys are App Events ( It contains sound files which play during any particular system events such as when you maximize your window), Control Panel ( contains setting regarding certain Control Panel icons), Keyboard Layout ( Cotains the keyboard layout as selected via Control Panel's Keyboard icon), Network ( It consist of setting related to mapped network drives) and Software ( Which has user-specific settings related to any application and Windows).

HKEY_LOCAL_MACHINE

HKEY_LOCAL_MACHINE (HKLM) contains non-user-specific configuration data for your system's hardware and applications. Three subkeys are used most often: Hardware( it contains subkeys regarding serial ports and modems as well as the floating-point processor), Software ( It comprise of computer-specific settings related to installed programs) and System ( It contains subkeys and settings related to Windows Startup).


HKEY_USERS

HKEY_USERS (HKU) contains settings that are similar to those in HKEY_CURRENT_USER. HKEY_USERS is used to store the settings for users with group policies defined, as well as the default settings (in the .DEFAULT subkey) which get mapped to a new user's profile.


HKEY_CURRENT_CONFIG

The settings related to the current hardware profile are inbuilt with HKEY_CURRENT_CONFIG (HKCC). If your system utilses only one hardware profile, HKEY_CURRENT_CONFIG is an alias for HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001. If your machine uses multiple hardware profiles, HKEY_CURRENT_CONFIG is an alias for HKEY_LOCAL_MACHINE\SYSTEM\ControlSetnnn, where nnn is the numeric identifier of the current hardware profile. This identifier is given by the CurrentConfig setting in the following key: HKLM\SYSTEM\CurrentControlSet\Control\IDConfigDB