Like many of you, I often help friends and relatives repair their systems. The problems they face can be just about anything, so to help diagnose the trouble and make repairs, I've created a collection of tools on a CDROM that I carry around with me. Here are the 10 most useful tools on that disc—I never leave home without it.

10. Firefox—The Mozilla Foundation's Firefox browser might not seem like a repair tool. But Microsoft Internet Explorer (IE) can become so corrupted by spyware that it no longer works, causing users to think their Internet connection is down. Often, installing Firefox immediately restores users' ability to connect to the Web, and users usually like Firefox better to boot. You can find Firefox at http://www.mozilla.org/products/firefox.

9. ZoneAlarm—Windows XP comes with Windows Firewall, which blocks only inbound traffic and doesn't give you any information about programs that are trying to access the Internet without-your knowledge. Of the firewalls available for free personal use, Zone Labs' ZoneAlarm is my favorite, and it works with Windows 2000 as well as with XP. You can download the free version at http://www.zonelabs.com/store/content/catalog/products/sku_list_za.jsp?dc=12bms&ctry=US&lang=en&lid=dbtopnav_zass.

8. FreeZip—To fix a system, I often need to take an action that requires unzipping files. Win2K doesn't include support for zipping and unzipping files, so my tools disc includes FreeZip, a free utility that can open, extract, and create .zip files. You'll find FreeZip at http://members.ozemail.com .au/~nulifetv/freezip.

7. Sysinternals Autoruns—The first place I go when a PC is having problems is into all the startup locations to see what programs are run when the system boots up. Sysinternals' Autoruns (http://www.sysinternals.com/Utilities/Autoruns .html) is the best utility I've found for that task.

6. Avast—I always install antivirus protection for systems that don't already have it. A few antivirus programs are free for personal use. The one I like these days is ALWIL Software's Avast 4 Home Edition (http://www.avast.com/eng/avast_4_home.html), which is available in both 32-bit and 64-bit versions.

5. Ad-Aware SE—Many systems have Microsoft Windows AntiSpyware installed, but that product doesn't remove some nasty spyware, such as SpySheriff and Cool Web Search. My CD-ROM includes Lavasoft's Ad-Aware SE Personal (http://www .lavasoftusa.com/software/adaware), which is free for personal use and does a good job of eliminating spyware, including types that some other products can't handle.

4. Memtest86—The tool I use to help diagnose hardware memory problems is Memtest86 (http://www.memtest86.com). Memtest86 builds either a bootable floppy disk or a CD-ROM ISO image that you can use to run memory tests.

3. Microsoft Windows Malicious Software Removal Tool—Many of the systems I see are infected with viruses, worms, or Trojan horses. The Malicious Software Removal Tool (http://www.microsoft.com/security/malwareremove/ default.mspx) quickly gets rid of most such malware. The Malicious Software Removal tool is updated on the second Tuesday of each month.

2. Magical Jelly Bean Keyfinder—I can't guess how many times I've needed to reinstall software only to find that the owner has lost his or her product key. So I now carry Magical Jelly Bean Software's Keyfinder, which can retrieve product keys for both Windows and Microsoft Office. The URL is http://www.magicaljellybean.com/keyfinder.shtm, but if typing it doesn't work, just do a Google search for Magical Jelly Bean Keyfinder and click the link.

1. BartPE—The most useful tool on my CD-ROM is BartPE (http://www1.nu2.nu/pebuilder). If you're not a Microsoft Software Assurance customer and don't have the Microsoft Windows Preinstallation Environment-(WinPE), you'll find BartPE extremely valuable. BartPE uses your Windows CD-ROM to create a bootable CD-ROM or DVD complete with a GUI, as well as command line, network, and NTFS file system support. BartPE is handy for working with systems that won't boot from the hard drive and for building and testing systems.