Damage to RAM installed in a computer is a common source of
system failures. Memory problems can prevent Windows from starting or can cause unpredictable stop
errors when Windows is already running. Memory-related problems
typically cause intermittent failures, and they are difficult to
diagnose without a special diagnostic utility. If you suspect memory
errors might be the cause of a computer problem, the special
diagnostic utility that you can use in Windows 7 to test your computer's memory is
Windows Memory Diagnostic.
You must run Windows Memory Diagnostic offline, but you can start the
tool in a number of ways on a system running Windows 7. From within
the Windows interface, you can schedule the tool to run the next time
the system starts. You can also start the tool through the Windows
Boot Manager menu or through System Recovery Options. Each of these
three methods is described in the following section.
Scheduling Windows Memory Diagnostic to Start
Although you cannot run the Windows Memory Diagnostic tool
while Windows is also running, you can use Windows to schedule the
utility to run automatically the next time the system starts. To do
so, click Windows Memory Diagnostic from the Administrative Tools
menu. Alternatively, you can click Start, type mdsched, select Mdsched from the Programs
list, and then press Enter. Either method opens the Windows Memory
Diagnostic window, shown in Figure 1.
In this window, you can choose either to restart the computer
immediately and check for memory errors, or to check automatically
for memory errors whenever you start the computer next.
Starting Windows Memory Diagnostic in Windows Boot
Manager
If you want to perform memory diagnostics and Windows is not
running, you can start the Windows Memory Diagnostic tool by
selecting it in Windows Boot Manager.
Windows Boot Manager is a feature that
enables you to choose an operating system to start when multiple
operating systems are installed on the local machine. Typically,
Windows Boot Manager does not appear when you have only one
operating system installed. However, you can force Windows Boot
Manager to appear by repeatedly pressing the spacebar as your system
starts.
When Windows Boot Manager does appear, press Tab to change the
selection from Windows 7 to Windows Memory Diagnostic, as shown in Figure 2. Then, press
Enter to start the diagnostic tool.
Starting Windows Memory Diagnostic from System Recovery
Options
The third way you can start the Windows Memory Diagnostic tool
is through System Recovery Options. Like the Startup Repair tool,
Windows Memory Diagnostic is available as an option on the Choose A
Recovery Tool page, as shown in Figure 3.
Running Windows Memory Diagnostic
Whichever of the methods you use to start Windows Memory
Diagnostic, the tool begins testing memory immediately when the
program starts, as shown in Figure 4.
Pressing F1 reveals the Windows Memory Diagnostic - Options page, as shown in
Figure 5.
As shown on the Options page, you can perform three levels of
testing: Basic, Standard, and Extended. Standard is the default
level; it performs eight types of tests. Basic performs only three
types of memory tests, and Advanced performs 17. Whichever level you
choose, the tests are performed twice by default. You can choose any
number of test passes between 1 and 99.
After Windows Memory Diagnostic completes testing, Windows
starts. On the desktop, Windows displays a notification bubble with
the test results, as shown in Figure 6. You can view
related events in the System Event Log with the source
MemoryDiagnosticsResults (event ID 1201).
If you do identify a memory failure, be sure to replace the
faulty RAM module. If the computer has multiple memory modules and
you are unsure which module or modules are causing the problem,
remove all modules except the first. Then, rerun Windows Memory Diagnostics to determine whether a
fault is detected. Next, remove the first module, insert the second,
and run Windows Memory Diagnostic again. Repeat the process for each
module that your system includes until you find the source of the
problem.
If problems persist even after replacing the memory, the
problem is likely to be caused by an outside source. For example,
high temperatures (often found in mobile PCs) can cause memory to be
unreliable. Although computer manufacturers typically choose memory
specifically designed to withstand high temperatures, adding
third-party memory that does not meet the same specifications can
cause failure. Besides heat, other devices inside the computer can
cause electrical interference. Finally, remember that motherboard or
processor problems may occasionally cause memory communication
errors that resemble failing memory.
