These remedies can get you out of some common jams without you having to call the computer maker's tech support. If none of these works, check the extensive knowledge bases at Microsoft's and Apple's sites. Updated drive software can usually be downloaded from the site of a device's manufacturer.

1. Trouble starting the computer with Window XP.  If you see nothing at all on the monitor, listen for beeping sounds after you turn the PC on. They are codes indicating internal problems (one beep usually means all is well). Find out what BIOS (system software) your computer uses; a PC displays it each time you turn the power on, just before Windows starts. Then check with the manufacturer of the computer or motherboard to decipher the codes, If the computer gets past the initial startup and hangs before Windows XP boots, try Microsoft’s step-by-step process at support.microsoft.com/kb/308041.

2.  No video or other display problem. Make sure the monitor is turned on. Raise the brightness and contrast controls. Try different resolution settings. To do that, you might have to start Windows in ‘safe mode'. Make sure the video card (inside the computer) is properly seated. Still nothing? It could be the driver for your display or video card, or the card itself.

3.  No sound. Try headphones or another pair of speakers to see whether the problem lies with the original speakers or your computer. If you still have no sound, check the Sound and Audio Devices settings in Windows’ Control Panel or download a new driver for the sound card.

4.  Printer isn’t working. Make sure there’s enough toner and ink (all colors). Check for paper jams. Use the print¬er’s self-cleaning feature. Be sure you’re using the right print settings. Use the printer’s self-test to see whether the print¬er is broken. Print a test page from other applications to see whether you can print at all. Still stymied? It could be a driver problem, especially if the printer spews out a string of hieroglyphics.

5.  CD or DVD won’t play. Dirt and smudges can prevent a disc from playing. Wipe the disc with a soft cloth, from the center to the outside. If it’s really dirty, wash it with mild detergent and pat it dry.

6.  Windows taskbar disappears. Move the mouse around the edges of your screen until the cursor looks like a double arrow, then left-click and drag the arrow away from the edge of the screen until you see the taskbar. To move the taskbar, click and drag on a blank area of it.

7.  Pointing device doesn’t work or jumps around. Try cleaning the mouse’s rollers or, if it’s an optical mouse, check for dirt embedded inside. Make sure the surface you’re using isn’t too shiny, which could keep the mouse from moving properly. If the mouse is frozen, restart the PC. If it happens often, get a new driver.

8.  A hardware device (such as a CD¬RW drive) won’t work. Uninstall the device from Device Manager, accessed via the Windows System Control Panel’s Hard¬ware tab. Then restart the PC. Windows should redetect and reset the device.

9.  Wi-Fi connection isn’t working. Big metallic objects or thick walls can block the signal. Reorient the router’s antenna or move the router. Check the antenna on any external Wi-Fl device to make sure it’s not broken.

10.  Can’t connect to Internet. Shut down the computer. Unplug the router and cable modem. Plug the modem back in first. Wait for the lights that indicate you’re connected to come on. If they don’t, the problem is with the connection and not the computer. Con¬tact your Internet service provider. If the lights do come on, wait 10 seconds, plug the router in, and start up the computer.

11.  Virus or spyware infection. Always have antivirus software and antispy¬ware installed on your system. If you suspect an infection, make sure that both have the latest updates, then run a complete scan of your system. If you don’t have working protection software, run a free virus scan at the site of a major vendor, such as Trend Micro or Panda Software.