Windows rehab 101

Before you put that ancient hunk of plastic and silicon to work, you need to clean it up and lock it down. Cleaning old software off the system will help it run smoothly, and securing it will help avoid headaches caused by worms, viruses, and other online nasties. Fortunately, you can do it all without spending a dime. Just follow this plan (for Windows XP and Windows 2000).

1. Clean it up

Windows craves system memory the way Oprah craves Oreos, and when it can’t find enough, it uses your PC’s hard drive to store temporary files, filling it up and slowing everything down. So you want to wipe the system memory of programs you don’t need and clear a wide swath on your hard drive.

Uninstall software you no longer need using the Add/Remove Programs tool inside Windows’s Control Panel. (You’ll find instructions for removing programs from XP here, and for Windows 2000 here).

If you’re not sure whether to nuke a program, just leave it. You don’t want to send Windows into a tizzy by accidentally deleting a system file. Try to free up at least 20 percent of the hard drive’s original capacity. To view a pie chart showing how much free space you have, launch My Computer, right-click on the drive letter (for example, “C:”), and select Properties from the popup menu.

To clear even more real estate, run Windows XP’s Disk Cleanup Wizard (click Start, then choose All Programs > Accessories > System Tools > Disk Cleanup). If you’ve got multiple drives, you’ll be asked to choose the one you want to clean up. Put check marks next to Temporary Files, Old Setup Software, the Recycling Bin and so on, then click OK and Yes to confirm. The steps for Windows 2000 are nearly identical; you can find them on Microsoft’s Windows 2000 troubleshooting page.

Keep unwanted software from loading into memory at startup

In XP, click the Start button, select Run, type “msconfig” in the box (without the quotes), and click OK. Click the Startup tab inside the System Configuration Utility box, and remove the check marks next to any programs you don’t need. (Again, if in doubt, leave it alone. If you’ve installed a WiFi adapter utility or a firewall, leave those checked.) You’ll have to reboot for the changes to take effect.

Windows 2000 doesn’t have an msconfig utility, so performing a “clean boot” may involve editing Windows’s Registry—a task for serious geeks only (see this page for more information). You can also speed up an old Win 2K system with minimal memory by following the steps laid out here.

Check your hard drive for errors

The older the system, the more likely it is that your hard drive has bad sectors and other age-related ailments that can crash Windows. To fix them in XP, right-click the drive letter in My Computer, select Properties, and click the Tools tab. Click the Check Now button for error checking, and put check marks in the boxes next to Automatically fix file system errors and Scan for and attempt recovery of bad sectors. You may have to reboot first. The steps vary only slightly for Windows 2000 (see the Windows 2000 troubleshooting page for more info).

Defrag your drive

Defragmenting your hard drive will speed things up by creating large contiguous chunks of space for Windows to do its work. As before, right-click the drive letter, select Properties and Tools, and click the Defragment Now button. Pick the drive you want to clean up, and click the Defragment button (for the skinny on how to defrag a Windows 2000 disk, see this Windows support article). This process can be painfully slow, so leave plenty of time, only do it only if you’ve got a small drive (less than 4GB) or the disk was totally packed.

2. Lock it down

The good news: Because you won’t be surfing the web or getting email on this PC, it’s unlikely to get infected by spyware or a computer virus. Your wireless router has a built-in network address translator (NAT) that hides your IP address from attackers, making it hard for some cyberstranger to plant a remote-access Trojan or other zombie-ware on the hard drive.

The bad news? There might be some evildoers lurking on that hard disk already. And if your wireless network hasn’t been secured, some digital delinquent could camp outside your house with a WiFi-powered laptop and hitch a free ride on your broadband connection-or worse, steal your data.

Scan your system

Several security-software firms, including BitDefender, Panda Software and Trend Micro offer free online virus and spyware scans. In many cases you’ll need to use Internet Explorer and download an Active X applet to run the scan. If the scan finds anything, you usually have to buy software to get rid of it. (Look for products that offer 30-day free trials, so you can cancel before you have to pay.)

Turn on the firewall

A software firewall adds an extra layer of protection, making your computer completely invisible to outside attacks. To turn on the one built into XP, click Start, select Control Panel, and launch the Network Connections applet. Under the Network Tasks column, select Change Windows Firewall settings. Put a check mark next to On (recommended), click OK, and close the Network Connections app.

Windows 2000 doesn’t have a built-in firewall, but you can download a free one from Sunbelt Software or ZoneLabs. Just launch the setup software and follow the prompts.

Turn off file sharing

This will keep other people who manage to sneak onto your network from snooping around your system’s hard disk. In XP, launch My Computer, right-click on the drive letter, and select Sharing and Security. If you’ve installed XP Service Pack 2, file sharing should be turned off by default. If not, make sure the box next to Share this folder on the network does not have a check mark in it. For doing the same in Windows 2000, see this page.

Secure your WiFi network

You can keep strangers from logging on to your wireless network or even knowing that you have one, but the exact steps will vary depending on the kind of router you have. Start by opening up your WiFi router’s settings page—you can usually get there by opening your browser and typing http://192.168.0.1/ or http://192.168.1.1/ into the address window (some routers may use a different address, so check the manual). You’ll have to supply a username (typically “admin” if you haven’t changed it) and password (often “password” or “public”; for a long list of default names and passwords, see this page). From there you can change your default username and password, tell your network to stop broadcasting its service set identifier, or SSID—essentially your network’s name-or turn on encryption/password protection. Without your SSID or your password, drive-by hackers won’t be able to log on (but if you forget them, neither will you, so write them down).

For more on WiFi security and drive-by hacking—also known as wardriving—see wardrive.net.

Award-winning journalist and proto-geek Dan Tynan is author of Computer Privacy Annoyances (O’Reilly Media, 2005).