Q: The screen has turned black on my wife's all-in-one PC, a desktop model on which the screen and computer are single unit. Only the cursor arrow is visible on the screen of her HP Omni model 120. What can we do?
Renato Bunal, Jacksonville, Fla.
A: If you're lucky, the problem can be solved simply. First turn off the PC and disconnect all accessories, such as USB flash drives or camera memory cards. Then unplug the power cord and hold down the PC's power button for about 15 seconds. Reconnect the power cord and turn on the computer.
If that doesn't work, there's other troubleshooting you can do, even though you can't see anything on the screen.
If you hear a beeping sound during start-up, HP says that a component inside the PC may be loose. While you could open up the computer case to look, I'd recommend letting a repair shop do it. Even a little static electricity from your body could wreck the sensitive electronic components.
If instead you hear the PC's cooling fan running during start-up, HP says you'll need to use keyboard commands to adjust either the PC's BIOS (basic input-output system) software or its power-management program. There's no room for error in these keyboard commands, so you'll need to view HP's precise directions on another computer (see tinyurl.com/ofqayb3).
Q: While at the St. Pete-Clearwater International Airport in Florida, I tried to access the airport's free public Wi-Fi network with my Nexus 7 tablet computer. The connection icon kept spinning, but I never got connected. Is this a problem with my tablet or with the signal strength of the Wi-Fi network?
Shirley Duerr, La Porte, Ind.