If Wi-Fi signal is MIA, go back to the installer

Q Several months ago we purchased a laptop computer and an 802.11n Wi-Fi router (which has typical speeds of 130 to 150 million bits per second), and had them set up by Best Buy's Geek Squad. Although the laptop "finds" the Wi-Fi signal easily, it often cuts out. Our other devices (an iPod Touch and the Nintendo DSi and Wii videogame machines) only "find" the Wi-Fi signal if we unplug the router and then plug it back in after a few minutes. This works, but it's a pain on a daily basis. What should we do?

NICOLE HAYES, BROOKLYN PARK

A You may have a system configuration problem or a router failure. It's also possible that your devices are barely within range of the router, and are getting a weak signal (router range varies with different types of house wall material.) Since you bought the equipment and installation service from Best Buy, ask them for free help.

But first check a few basic things. Have you installed any new software since the system was set up? If so, try uninstalling it to see if there's a conflict between the program and the router.

Are you using antivirus and firewall software to protect your PC? New computers sometimes come with free-trial software that lasts only a month or two.

Q I bought a new HP Photosmart C-4480 printer about a year ago. I replaced the black ink cartridge with a cartridge from a different vendor, and it worked fine for some time except that I got no indication of how much ink was left. Then the printer quit working and I got the message "incompatible ink cartridge."

I think HP software updates caused this to happen. But if HP sells a printer that works with other vendors' cartridges, it doesn't seem right that they can do this. Is there any way to get around it?

A Computer printer manufacturers tend to make little money by selling printers, but a lot of money by selling replacement ink cartridges. It's the famous "give away the razors and sell the razor blades" business model.

As a result, HP doesn't encourage the use of non-HP ink cartridges, and its warranty won't cover problems related to them.

One way around this is to refill your HP ink cartridges. See a video demonstration at tinyurl.com/297qp8j. Bulk ink to refill the cartridges can be purchased online from websites such as The Printer Ink Warehouse (tinyurl.com/24zg8lr) and Printer Filling Station (tinyurl.com/28mcbnz.) You can also get refills at some stores, including Walgreens and Cartridge World.

However, HP says refilling its cartridges can cause quality problems. See tinyurl.com/2dr5n7j.