Anyone who has ever done desktop support in any capacity, whether it was for an office with hundreds of employees or just for your family, knows that calling to get warranty support can be one of the most frustrating aspects of the job. You’ve got to run through a troubleshooting script with someone who assumes you don’t know anything, and there’s no secret code that techs can use to signify that they know what they’re talking about. You can get bumped from department to department before you finally talk to someone who can help you, and often have to re-state your name and all of the pertinent information each time. It’s a huge time sink, and it’s one I prefer to avoid if at all possible.

Learning how to expedite this process is a vital part of any technologist’s skill set. So, drawing upon years of sad practice, we’ve put together a master guide to troubleshooting for PCs, Macs, phones, and tablets in a way that should minimize the amount of time you spend on the phone with support people who are always going to start by asking you whether your broken hardware is plugged in.

Known-good parts: the troubleshooting silver bullet

Before we get into specific symptoms and fixes, there's one silver bullet that's guaranteed to get you past most of the support person’s troubleshooting script and right to what you want: the known-good part. That is, a power adapter, stick of memory, hard drive, or other component that has been plugged into another system and is known to be working properly.

Let’s say you’ve got a laptop that won’t power on. If you switch its power adapter for one that is known to work (or if you use its power adapter with a laptop that will power on and charge), you can say with a fair degree of certainty that the power adapter is not the problem. This method does require you to have working spare parts available for testing. But if you tell a phone tech that you’ve tested a particular problem with known good parts, you’ll automatically skip through a lot of the script—and quite possibly to the end of the conversation.

PC troubleshooting

PCs are always getting simpler and more streamlined, but there are still a lot of different parts to most of them, which means that there is a lot more that can go wrong with them. We’ll go through potential problems component by component, matching symptoms to issues and telling you the best way to inform your friend on the other end of the phone. Pay attention here, because many of these symptoms and procedures are also going to be useful when troubleshooting Macs, phones, and tablets.

Some computer manufacturers may ship (or make available for download) special diagnostic tools intended to detect problems with particular components. It's not always necessary to use these tools to diagnose problems, but getting support will often be easier if you have the error messages and codes generated by their tools. Having these error codes handy is the ultimate phone support shortcut, and if you open with them, you’ll almost always skip straight to the part where they set up the dispatch for you.

Power problems

Symptoms: Computer won't power on, battery won't charge.

If the computer simply isn't responding to any attempts to turn it on, you may be having power problems. Remember that there's a difference between not powering on and not booting—a computer with power problems won't light up or make any noises when the power button is pressed. If lights and fans are coming on but the operating system won't load, you may have a memory, hard drive, or even motherboard error instead.

As a first step, unplug the computer from power and remove any batteries, then press and hold the power button for 10 to 15 seconds. This will completely power cycle the computer, draining out any electricity that may be left lingering in its circuits (some desktop motherboards have a light on the motherboard that will stay on for a while after the computer has been unplugged—once this light goes out, you've discharged all of the power). If you plug the computer back in and still have no luck, it's time to start troubleshooting the different stages of the journey between the wall and the computer:

Start with the surge protector. Does the computer behave the same way if connected directly to the wall, or to another outlet that is known to be working normally?

Look at the power brick if you've got a laptop. Most power bricks have two cords: one that runs from the outlet to the brick, and one that runs from the brick to the computer. If either of these cords can be detached from the brick, try again with a known good cord if you have one. If you've got a desktop, you'll usually just have one cable to check, the one that goes from the outlet to the back of the computer. If your laptop’s cables and adapters are working normally, you’ve probably got a motherboard problem, and it’s time to call support.

If you’ve got a desktop, your problem could be either with the motherboard or with the system’s internal power supply. Again, a known-good power supply will tell you exactly which is the problem, but be sure to check for things like the aforementioned motherboard status light—if it lights up when the computer is plugged in, it may point to a motherboard issue rather than a power issue.

If your computer will turn on but your battery won’t charge, you’ve almost certainly got a bad battery. As always, try a known good battery in the computer (and, if you can, try the suspect battery in a laptop that is known to charge) and make sure it’s not an issue with the contacts in the computer.

If you do have a bad battery, it likely isn’t covered under warranty unless it failed prematurely. If the battery is less than a year old, you may be able to get a replacement. But if the battery is over a year old, any loss of capacity or breakage will generally be seen as “normal wear and tear” and you’ll have to buy a new one. Most laptop manufacturers will insist you buy a first-party battery to avoid voiding the warranty on the rest of the computer.

Memory

Symptoms: Blue screens or crashing applications, computer powers on but will not boot, other erratic behaviors.

Memory errors can be hard to diagnose since they're often intermittent, but they present most often as general system instability: individual applications or the entire operating system may crash, the system may sometimes refuse to boot. And you may even experience graphics corruption, since the integrated graphics processors used by many computers today use the same memory as the rest of the system.

For more serious memory errors, the computer may power on and beep or make the power light flash a certain number of times without attempting to boot from the hard drive. Consult your computer's manual to see if these correspond with any known error codes.

Your first step in troubleshooting this problem is going to be a good memory diagnostic tool. Some computers will have a memory test tool built into the BIOS; the vendor’s support center will typically ask for error codes generated by those tools when replacing memory. But there are some good general-purpose alternatives if your computer shipped without one of these tools. Windows 7 comes with its own memory diagnostic, which can be run from within Windows 7 or from the Windows 7 install media.

My personal favorite memory test tool is Memtest86+. To run Memtest, you’ll need to download its disk image, burn it to a CD, and then boot your computer off the CD. The tool will automatically start testing your memory and will keep making additional passes until you shut the computer off. Generally, if the tool hasn't found an error after two or three passes, it's not going to.

Once you’ve verified that you’re dealing with memory errors (and assuming that your computer has multiple memory modules installed, as almost all of them do these days), take each module out and test it individually. This can help you isolate the issue to one of the RAM modules. Once you’ve got a module that you know is good, be sure to test it in all of the slots as well—this will reaffirm that the problem is with the memory stick and not with one or more of the RAM slots on the motherboard.

Hard drive

Symptoms: Slow or inconsistent performance, errors when attempting to access files, computer unable to boot, louder-than-usual drive clicking or activity noises (for mechanical HDDs only).

Losing the hard drive in a computer is one the most devastating failures you can experience, since the data is often the most valuable part of the computer. Even if all of the other components fail, the drive can still be pulled and the data transferred. But data recovery services for failed hard drives can cost thousands of dollars, and they aren’t foolproof. If you don’t have a good backup system in place (and you should: there are plenty of products that do it), you should be checking your drive for errors regularly—detecting a failure early is the best way to prevent data loss.

As with RAM, some manufacturers (particularly business-class systems from the likes of Dell or HP) include their own diagnostic tools with their computers, either in the BIOS or on a disc—if they do, they’ll prefer data gathered with those tools to data gathered by others. Even so, you can generally convince them that you’re having problems if you tell them you’re experiencing one or more of the symptoms listed above along with confirmed bad sectors found by a tool like Microsoft’s Chkdsk. Whatever tool you run, it’s vitally important that you back up any data from a suspect drive before you run any of these scans, as they are quite intensive and may actually exacerbate problems in the process of detecting them.

Chkdsk is normally run in one of two ways, depending on whether you can get your computer to boot or not. If your computer can boot, you can initiate the scan from within Windows. In a Windows Explorer window, go to Computer and right-click the drive you’d like to scan. Click Properties in the menu that pops up. In the properties box for the drive, under the Tools tab, click “Check now” under the Error-checking section, check “Scan for and attempt recovery of bad sectors,” and click Start. The computer will then offer to schedule a disk check for the next time you start the computer; accept the prompt and restart the system.

When the disk check is done, it will display the results of the scan, but they’ll likely flash by so quickly that you'll miss them. To see this log file after the fact, open up the Windows Event Viewer (type “Event Viewer” into the Start menu’s search field and it should come up), expand the “Windows Logs” drop down, and select “Applications.” The Chkdsk log should be near the top of this list (the Source column should say “Wininit”), and if you scroll down under the “General” tab you should see the results of your test, as shown in the screenshot below. If you see anything more than “0 KB in bad sectors,” you should replace that drive—it’s not long for this world.

The other way to run Chkdsk is from the Windows install media—we showed you how to get this in a previous article. Boot to the media and before you do anything, press Shift+F10 on your keyboard to bring up a command prompt window. Type chkdsk c: /r (assuming the drive you want to check is drive C) and wait for the results. Again, anything more than 0 KB in bad sectors on the disk means that it’s time for a replacement.