Troubleshooting and Maintaining Your PC All-in-One For Dummies. Dan Gookin

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СКАЧАТЬ switch. This switch can trip for a variety of reasons, which cuts power to the circuit. Check for an RCD power receptacle and punch the Reset button to reactivate the circuit.

      ❯❯ If the RCD switch trips after you press the Reset button, call an electrician.

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Avoid the temptation to run your PC from an uninterruptible power supply (UPS) during a dip or power outage. Use the UPS power only to save your stuff and then properly shut down the computer.

      ❯❯ Some UPSs beep during a dip. A few models feature digital displays that may graphically show that the incoming voltage level is subnormal.

      ❯❯ It’s possible to use a laptop when the power is off – well, if the laptop has a charge in its battery and nothing else is awry.

      “DID MY PC SECRETLY RESTART?”

      If you leave your computer on all the time, you may show up one morning and discover that Windows has automatically restarted itself; rather than see the desktop, you see the logon screen.

      The main reason the computer has restarted itself is that the Windows Update utility has installed a required update. That’s okay. You can direct Windows Update to prompt you, but it may still restart the computer. See Book 4, Chapter 1 for more information on Windows Update.

      If the computer restarted and no updates were installed, the power company might be to blame. The computer might also have a power glitch, though if that were true, you’d see other, random restarts at various times during the day.

      Phase II: The POST

      When abuzz with electricity, the computer’s internal components spring to life. It might be a chaotic ballet of confusion, but one thing is in charge: the processor.

What happens

      The processor, also known as the central processing unit (CPU), is the computer’s main chip. It’s the boss. The main dude. El Comandante Supremo. After the power starts flowing in, the processor jumps (figuratively) to a specific code in memory, where it begins executing instructions. Those instructions place the computer in a diagnostic, or self-checking, mode. The computer inventories its various components.

      A POST, or Power-On Self Test, is performed, in which the computer checks its own hardware. Memory is tested and its quantity determined. Control is passed to various subsystems (network, video, audio, and power management, for example), which also perform their own inventories and tests.

      Information may be displayed on the screen as feedback during this stage. Most PCs, however, display a startup, or splash, screen. The screen may or may not divulge what’s happening inside the computer. When it does, you may see a memory count or seemingly random numbers or a copyright notice. That diagnostic information is intended for troubleshooting (very nerdy troubleshooting, as in oscilloscope troubleshooting).

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One important message revealed at this point is which key or key combination to press to enter the computer’s Setup program. See the section “Phase III: Startup Options,” later in this chapter.

      ❯❯ Just because hardware passes the POST doesn’t mean that everything is well. Computer hardware also needs software to control it. If the software isn’t working, a problem may still appear.

What could go wrong

      Video problems present themselves through a series of beeps. The beep pattern reveals the problem, though if you hear beeps but see nothing displayed, the PC’s power supply or display subsystem is at fault.

      When the power supply and display subsystem are working, problems with other devices are indicated by messages appearing on the screen.

      A common error you might see at this stage is a CMOS error, which means that the PC’s battery-backed-up memory has failed. This error manifests itself through a missing boot drive or another inventory problem. The computer’s time may also be off. Fortunately, this type of issue is limited to very old PCs.

Troubleshooting steps

      Because hardware fails when the computer starts, the first solution is to replace the defective hardware. The message on the screen indicates what the problem child is, such as the video system or network or another subsystem. Make a note of whatever error message appears. Then deal with the issue by replacing the hardware. This step includes replacing the CMOS battery, should it fail.

      ❯❯ If the motherboard or chipset is to blame for the problem, the best solution is to get a new PC. You can replace the motherboard, but it’s not cheap. Further, the motherboard may not be the problem.

      ❯❯ Failed network firmware is fixed by installing a USB network adapter.

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To discover which motherboard you use, pay close attention to your PC’s splash screen. The motherboard (or chipset) manufacturer, as well as the version number, is often displayed. You can also run the UEFI program, as described in the next section.

      ❯❯ Don’t think that every code you see on the splash screen is a POST error. Many computers display information during startup that is completely normal and expected.

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The computer may continue to start, even with defective hardware flagged by the POST. That’s not an excuse to avoid fixing it.

      ❯❯ A common POST error is a missing input device, such as the keyboard or mouse. In fact, one of the most comical error messages from the early days of the PC went something like this:

      Keyboard missing, press any key to continue

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Another startup issue at the POST phase is the BIOS password. This isn’t as big of an issue as it was years back, but my advice remains the same: Do not use the BIOS password.

      Phase III: Startup Options

      After the POST passes, you may see a series of startup keys displayed. These keys don’t indicate any problems. On the contrary, the keys and their options are presented to help you troubleshoot the PC.

What happens

      You see a menu displayed, listing keys and their functions. It may look like this:

      F2 – Enter Setup

      F7 – Update BIOS

      F10 – Select Boot Device

      The keys and their commands are different for each type of motherboard. Sometimes, the keys aren’t displayed at all, but they may still be available.

      The keys control several actions that can take place after the POST and before an operating system is loaded. Here are what the keys could do:

      Enter Setup Program (UEFI): The UEFI is the successor to the old BIOS Setup program. It provides a summary of installed features, basic hardware configuration, and other options.

      Update the BIOS (Firmware): This option is available, though most BIOS updates are performed from Windows.

      Select СКАЧАТЬ