If you have Adobe Photoshop, this program opens picture files because it has been associated with them. However, using Adobe is an awkward situation because it is slow to open and places the picture in a work environment, thus there are much better programs for viewing pictures. When you click on a file that ends in .jpg, the photo editor that you use does the same thing. WinXP uses Windows Picture and Fax Viewer. You can also view them in Internet Explorer, or you could use Windows' Paint program.

Should you have problems opening a file in a particular program, first open any Windows folder. With the folder open, click on Tools. It reveals a menu that includes an item called Folder Options. Once you're there, click on File Types. Now you'll see a long list of file types. They're identified by the extension in the last part of the file name. You'll see extensions such as .doc and .jpg, among others.

Next scroll down until you see a file you want opened which would not open in its normal program. Highlight it by single clicking on this file and then clicking on the button that says Change. You'll see a list of the programs installed in your computer. Select the program you want to use to open that file type. From then on, you simply can click on any file with that extension and the program you selected will open it automatically.

In summary, to change the association in XP, go to Windows Explorer, rightclick the picture file you want to open, select Open With, click Choose Program, select the program, click the box that says "Always use the selected program to open this kind of file," and then click OK. This process works with any program, not just pictures. It works the same way in Windows ME. With Win98, go to Windows Explorer, click View, Folder Options, and select File Types. Highlight the file type (in this case, .jpeg) and click Edit. In Actions, click Open, and click Edit. Find "Application used to perform action," click Browse, select the program you want to use, and click Open.

File Extensions
Executables: An executable (.com or .exe) lists machine-language instructions that a computer can understand and execute. Don't launch executable files that you receive from an unknown source, such as an unsolicited e-mail. Many worms propagate via e-mail address books even if you may know the purported sender of an infected file. Also don't open any executable file until you have confirmed by phone or e-mail that the file is virus free. By extension, .bat (batch files) and .cmd (Windows batch files) include executable commands and may also contain a malicious code.

Script teasers: Scripts are pieces of human- readable programming code that services translate into machine-code instructions and execute. The script file extensions to be concerned with include those that work with Windows Script Host (.ws, .wsc, .wsf), JavaScript (.js), and Visual Basic (.vb, .vbe, .vbs).

Other service-launching extensions: If you double-click a file whose extension is associated with a Windows service, that service will open and run using the information in the file you double-clicked which contains instructions for the service. Such extensions include .pif (a program information file that tells Windows how to run an old DOS app), .msi (a Windows installer database), .hta (an HTML application), and .scr (a screen saver).

Space savers: If you are tired of the screen savers on your system, save disk space by searching for all of your system's .scr files (enter *.scr as the file name you're searching for) and deleting the unwanted ones. For instant privacy, use the right-mouse button to drag any .scr file to your desktop or the Start menu (or one of its submenus), and choose Create Shortcut(s) Here. Just click the shortcut to launch the screen saver, and tap a key or wiggle your mouse to turn it off.

Control Panel icon elimination: When the culprit is not one of Windows' control panels but an uninvited intruder installed by some other program, it's useful to know that most Control Panel icons represent files with the .cpl extension. Enter *.cpl in the file-name field of Windows' search function to list the Control Panel applets on your system. Doubleclick each file until you find the one that you don't need on your computer. Move the unwanted file to another folder, or make a backup copy and delete the original. In some cases multiple icons in the Control Panel window may represent a single .cpl file. For example, removing main.cpl will eliminate the Fonts, Keyboard, Mouse, and Printers icons.

System secrets: Some system file types don't run by themselves and don't open in an application. Other programs on your computer use these files to get information about the machine's settings, special programming functions, and other resources. You can customize your system by editing certain .ini, .inf, and other system files. One common system file type is the dynamic link library, or .dll. Sometimes multiple applications will install one .dll file, potentially causing conflicts. To help advanced users sort through .dllrelated problems, MS has set up a searchable database that they can use to ferret out the purpose of any MS .dll file.

Wascally Wegistwy files: Exported portions of the Windows Registry have the .reg extension. When editing the Registry do so with caution. These files serve as small, targeted backups of the portion you'll be working at this location. Click Start, Run, type regedit, press Enter, navigate the tree pane on the left or use the Edit, Find feature, and click the section of the Registry you plan to edit.

Next choose Registry, Export Registry File, make sure that 'Selected branch' is highlighted, specify a name and a location to store it in, and click Save. The settings for that portion of the Registry will be saved as a file with the .reg extension. If you make a mistake, you can restore that portion of the Registry to its prior state by double-clicking the backup file and then following the on-screen prompts. You're not likely to encounter a problem with .reg files that you make yourself, but beware of unknown or unsolicited .reg files! If merging a corrupt, outdated, or malicious .reg file, you can damage your Windows settings.

Folder Icons and Pictures: WinXP includes more than 200 icons that can be used instead of the standard yellow folder. To change them in XP, first go to Windows Explorer (Start, All Programs, Accessories, Windows Explorer). Rightclick on the folder you want to change, click Properties, and select the Customize tab. At the bottom of the window, click the Change Icon button. It will present you with more than 200 icons. After finding one you like, click it, OK, and then click Apply and OK again. You also can place pictures within the folder icons. However, you can only use Thumbnails view (click View, Thumbnails). The picture must already be on your hard drive. You can scan the picture in or download it from the Internet or a camera and then save it as a JPEG (.jpg). To place a picture within an icon, go to the Customize tab as before and click Choose Picture. At the top of the Window, navigate to the picture on the hard drive, click it, Open, and then click Apply, OK. Custom icons also can be designed in Paint, which is part of Windows (Start, All Programs, Accessories, Paint), and click Image, Attributes. Height and width should be set to 32 pixels. After your design is drawn, click File, Save As. Save it to any folder on the hard drive. Users of Win98/ME/ 2000 can use software to change icons. Here are some free programs: IcoFolder and ActivIcons.

Help Site: This WinXP site contains over 100,000 messages. Its Tweak & Tip Database has separate categories for usability, user interface, system performance, Internet, networking, etc.

Internet Connection Firewall
The ICF that comes with WinXP does an important job of blocking unsolicited incoming traffic from the Internet. To activate the ICF, on any computer directly connected to the Internet, double-click My Network Places and click View Network Connections. Click the Advanced tab, check the box under ICF and click OK. If you have several computers sharing an Internet connection, activate the ICF on the computer with the primary connection.

Message Bubbles
Messages in the form of newspaper bubbles appear whenever you hold a mouse pointer over the Start button or icons in the Quick Launch bar. If you want to remove them, right click the icon, click Properties, go to the Shortcut tab, and delete everything in the comment box. On the General tab, you can edit but not delete the icon's title in the bubble.

Movie Maker
Many digital cameras include basic video-editing software. Check the software that came with your camera. If you are using WinME/XP, check out Windows Movie Maker. This little program is provided free with Windows. You'll find it at Start, All Programs (in WinME, Programs), Accessories. To use it, first import the clip from the camera to your hard drive. Then click File, Open Project, navigate to the clip file, and click Open. Movie Maker allows you to add titles and trim the clips.

Narrator
WinXP provides an additional accessibility tool for the vision- impaired user. Narrator reads all text aloud. A quick way to get there is by pressing the Windows key + U. An alternative option is to select Start, Programs, Accessories, Accessibility, Narrator.

Network Status
To check the speed of your ISP connection, activate the Network Status icon, which resides in your System Tray. You can rightclick it to find your ISP connection's speed and close the connection. To find it in WinXP, click Start and select My Computer. In the Other Places menu, click My Network Places. In the Network Tasks menu, click View Network Connections. Right click the icon of the ISP connection or network and select Properties. On the General tab, check the box for "Show icon in notification area when connected" and click OK. Users of Win98 can also activate the icon by opening Windows Explorer and clicking Dial up Networking. Right click the connection in which you are interested and click Properties. Select General and click "Configure in the Connect Using area." On the Options tab, click the box for "Display modem status" and then click OK. Whenever you connect to your ISP, the icon will appear in your System Tray.

Finally, in WinXP if you're plagued with Messenger pop-ups, right-click My Computer and select Manage Service and Applications Services. Double-click the Messenger entry, select Disable as the Startup type, and then click on Stop and Apply.