What type of software can you run to help fix computer problems?

In addition to basic Hand Tools for Computer Repair, you may need some software tools to diagnose and troubleshoot problems and to recover from them. The conundrum, of course, is that most diagnostic software utilities run under Windows, but quite often when you're troubleshooting it's because Windows won't load or run because it's corrupted itself or been damaged by a virus or worm.

Fortunately, there's an alternative. A "Live Linux CD" such as Knoppix (http://www.knoppix.org), shown in Figure 2-3, allows you to boot and run a full-featured Linux operating system directly from the CD, without altering the contents of your hard drive. Knoppix and similar Live CD distributions include a plethora of graphics-based tools that allow you to diagnose, test, and burn-in the various hardware components of your system.

Figure 2-3: The Knoppix desktop

Knoppix is priceless when you need to recover data from a corrupted or otherwise inaccessible hard drive that Windows won't touch. Figure 2-3, for example, shows Knoppix running on a system that had crapped out under Windows. Windows refused to boot, and we didn't want to risk a reinstall before we salvaged the data on the drive.

Knoppix gave us read-only access to the Windows partition, and allowed us to browse it and copy the data files to a safe location. Knoppix even recognized the Windows network we were connected to, and allowed us to save the recovered files to a shared Windows volume on another machine on the network. If the machine hadn't been connected to a network, we could have used K3b (a Linux CD/DVD burning application) to write the recovered files to a CD or DVD all of this simply by pointing and clicking, just like Windows. You don't need to learn Linux to use Knoppix.

We don't have room here to detail all of the many capabilities of Knoppix. Download a copy for yourself (now, before you need it) and play around with it. Search Google for "Knoppix recover" or "Knoppix rescue" and you'll find dozens of documents that explain the hardware analysis, testing, and data recovery features of Knoppix. Oh, did we mention that Knoppix is free for the download? Knoppix is also available on CD for a nominal fee from online vendors like CheapBytes (http://shop.cheapbytes.com) and many others. For plenty of information on all that you can do with Knoppix, see Knoppix Hacks (O'Reilly, 2004).

When Windows is running, you might also want a general Windows-based diagnostic utility. The best diagnostic utility we know of is Everest Home Edition, from Lavalys Consulting Group, Inc. (http://www.lavalys.com; $30, free trial available), shown in Figure 2-4. Lavalys sells versions with additional features, but for diagnosing and repairing a home PC, the trial version should get you by.

Figure 2-4: Everest general diagnostic utility

You may also find some or all of the following items useful for various tasks:

You need the OS distribution discs to replace a failed hard disk, but you may also need them for routine upgrades and maintenance. For example, Windows prompts for the distribution disc to load drivers for a new device, and Linux distribution discs may contain hundreds of programs that weren't loaded during the initial installation. If you've updated the operating system from the initial distribution version (that is, by applying a Windows Service Pack), also keep the Service Pack or update CD handy.

If you use a third-party backup utility, keep a copy of the distribution CD in your kit to make sure that you can restore backups after reinstalling the operating system. Few things are more frustrating than getting a failed computer up again and having a good backup, but not having the software at hand that you need to restore it. Research backup tools well. For example, one of our tech reviewers notes that Nero's BackItUp 6 ate data from a relative's network storage drive the only place where that data was stored.

Any time a Windows system behaves oddly, your first step should be to scan it for viruses, Trojans, and worms. In fact, it's a good idea to scan any Windows system regularly even if it's operating normally, because recent viruses and worms avoid overtly hostile behavior. Instead, they take control of the system unobtrusively and use it to relay spam, host porn files, launch DoS attacks, and so on. The most popular AV products are sold by McAfee and Symantec (Norton), but we suggest you avoid them. Our own experience and reports from our readers suggest that these bloated products cause nearly as many problems as they solve. We recommend Grisoft AVG Anti-Virus (http://www.grisoft.com), which is free for personal use, seems about as reliable as any of its competitors, and uses few system resources.

Spyware and adware, which we refer to collectively as malware, are close cousins to viruses, Trojans, and worms. The least malicious forms of malware may simply display ads and perhaps report your web browsing activities to a central server. Malignant forms of malware may capture passwords, bank account and credit card information, and other private personal data and relay that information to criminals who use it to steal your identity and empty your bank account. Standard antivirus software doesn't detect most malware. To do that, you need a malware scanner. We recommend AdAware (http://www.lavasoftusa.com) and Spybot Search & Destroy (http://www.safer-networking.org), both of which have versions that are free for personal use. (Use both, because each detects problems that the other does not.)

Memory errors are among the most commonly encountered hardware problems. The trouble is that such errors may be caused by defective memory or by a marginal or failing power supply. The best way to determine the cause of the errors is to use a memory testing utility such as MemTest86 (http://www.memtest86.com) to isolate the errors. If the errors occur reproducibly at the same physical memory addresses, the most likely cause is a defective memory module. If the errors appear at random memory addresses, it's more likely that a marginal or failing power supply is the problem. MemTest86 is available as a bootable floppy disk or a bootable ISO CD image, and can usually be run even when memory errors are so severe that Windows or Linux cannot load. (If you're running Knoppix, just type memtest and press Enter at the boot prompt to run memtest86.)

Recent versions of Windows and Linux allow you to create an emergency disk that contains critical system configuration data, part or all of the registry, and so on. Create or update this disk for a computer any time you make a significant change to it. Label and date the disk and store it near the computer or keep it with your toolkit. If you don't have a recent copy, do yourself a favor and make one right now. Use the following procedures and tools to create an emergency disk:

Run Start Programs Accessories System Tools Backup. With Backup running, click the Emergency Repair Disk icon (ASR, or Automated System Recovery, in Windows XP) to create the disk. In the resulting dialog, check the Also backup the registry box to copy key system files to the repair directory on the hard disk. The Windows 2000/XP ERD is not bootable. To repair Windows 2000/XP, you must boot either from the distribution CD or the boot floppies and initiate a repair from the boot menu. You'll be prompted to insert your repair disk at some point in the procedure.

The Windows 2000/XP ERD does not contain any registry files. Creating the ERD copies the registry files to the %SystemRoot%\ Repair folder, where they may be lost if the hard disk crashes. To be safe, before you create or update the ERD, copy the entire contents of that folder to another hard disk, network volume, or optical disc. (The repair folder will be empty if you've never run Ntbackup.)

Use the mkbootdisk command to produce an emergency boot floppy disk. This disk is specific to your system configuration, and should be updated any time you make significant hardware or configuration changes.

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