Q: I have a work space in my new garage, but I can't get access to my house Wi-Fi network from there. This is happening even though the garage is only about 150 feet from the house, and I just installed a new Wi-Fi range extender that was supposed to boost the signal. Comcast, my Internet ­service provider, said it can't provide a separate wired Internet connection to my garage because the garage doesn't have its own street address. What can I do?

Meagan Smith, Mahtomedi

A: Wi-Fi has trouble passing through some types of walls, and if the ­signal has to penetrate several walls the problem gets worse. By the time the Wi-Fi signal gets outside of your house, it probably doesn't have enough strength to reach across another 150 feet of space and through the garage wall.

The easiest fix would be to use a USB Wi-Fi antenna (about $20) with your PC. It should be able to detect a faint Wi-Fi signal in the garage.

If that doesn't work, improve the path the Wi-Fi signal has to travel to reach the garage. Have Comcast move your Internet connection to a house wall outlet closer to the garage, preferably near a window with line-of-sight to the garage. Wi-Fi signals penetrate glass better than walls.

If that's not possible, you can move your Wi-Fi router to a window facing the garage. But you'll have to attach it to your modem by a long cable (use "Category 5 enhanced cabling," or Cat5e.)

If that still doesn't allow you to get a Wi-Fi signal in the garage, you can try extending a Cat5e cable from the cable modem to the garage (by passing it around the edge of a window or door), then plug the cable into your PC. As long as the cable is no more than 300 feet long, the signal strength should enable you to get an Internet connection.

Q: I have an annoying computer virus that generates pop-up advertisements constantly. Some of these ads give toll-free numbers to call to get help eliminating the pop-ups. I think the virus is called SaleHelp, but I can't be sure because I can't find the program anywhere on my PC. How did I get this, and what can I do to get rid of it?

Kent McKee, Jacksonville, Fla.

A: What you have sounds like SalePlus, a well-known adware program that displays pop-up ads and is difficult but not impossible to eliminate. The directions to get rid of SalePlus are at tinyurl.com/l3p5ju7. You can safely use the three recommended free security programs, AdwCleaner (tinyurl.com/kgp57wp), Malwarebytes (tinyurl.com/dx3u46y), and HitmanPro (tinyurl.com/6cev7t.)

You probably acquired the adware as an optional extra piece of software when you downloaded a legitimate free program. If you're given the choice, always pick "custom installation" when downloading free software. That allows you to uncheck the boxes for additional programs, such as SalePlus, whose real purpose doesn't become clear until later.

E-mail tech questions to steve.j.alexander@gmail.com or write to Tech Q&A, 650 3rd Av. S., Suite 1300, ­Minneapolis, MN 55488. Include name, city and telephone number.