CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [299]
SFC /scannow
SFC automatically checks all critical files and replaces any it sees as corrupted. During this process, it may ask for the Windows installation CD-ROM, so keep it handy!
System Restore
With Windows XP and Vista systems, you can recover from a bad device or application installation by using System Restore to load a restore point. Follow the process explained earlier in the chapter. System Restore is the final step in recovering from a major Windows meltdown.
Application Problems
Almost all Windows programs come with some form of handy installer. You run the installer and the program runs. It almost couldn’t be simpler.
A well-behaved program should always make itself easy to uninstall as well. In most cases, you should see an uninstallation option in the program’s Start menu area; and in all cases (unless you have an application with a badly configured installer), the application should appear in either the Add/Remove Programs or Programs and Features Control Panel applet (Figure 17-62).
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NOTE Remember that you need local administrator privileges to install applications in all versions of Windows.
Despite Microsoft’s best efforts, you can run into trouble with applications. Although these errors come in hundreds of varieties, the overwhelming majority of problems can be broken down into three categories: installation problems, compatibility problems, or uninstallation problems.
Installation Problems
Programs that fail to install usually aren’t to blame in and of themselves. In most cases, a problem with Windows prevents them from installing, most notably the lack of some other program that the application needs so it can operate. One of the best examples of this is the popular .Net Framework. .Net is an extension to the Windows operating system that includes support for a number of powerful features, particularly more powerful interface tools and much more flexible database access. If a program is written to take advantage of .Net, .Net must itself be installed. In most cases if .Net is missing, the application should try to install it at the same time it is installed, but you can’t count on this. If .Net is missing or if the version of .Net you are using is too old (there have been a number of .Net versions since it came out in 2002) you can get some of the most indecipherable errors in the history of Windows applications.
Figure 17-62 Programs and Features Control Panel applet
Figure 17-63 shows one such example in Windows 7 where the popular VMware vSphere client fails due to the wrong .Net version. Too bad the error doesn’t give you any clues!
These types of errors invariably require you to go online and do Web searches, using the application name and the error. No matter how bad the error, someone else has already suffered from the same problem. The trick is to find out what they did to get around it.
Compatibility
Most applications are written with the most recent version of Windows in mind, but as you know, Windows versions change over time. In some cases, such as the jump from Windows 2000 to Windows XP, the changes are minor enough to cause few if any compatibility problems when running an application designed for an earlier version of Windows. In other cases, especially the jump from Windows XP to Vista (and beyond), the underpinnings of the OS differ so much that you have to perform certain steps to ensure that the older programs run. Windows 2000, XP, and Vista provide different forms of compatibility modes to support older applications.
Figure 17-63 .Net error
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NOTE Although it’s sometimes a challenge to get an older application to run on a newer version of Windows, the opposite is no problem at all: Installers know to check Windows versions and pop an