QI was on a NASCAR website when a flashing box appeared on the bottom of the screen. It said I was the 1 millionth reader and had won a $1,000 gift certificate to Walmart. When I clicked on the box, a screen full of questions came up; they asked for my e-mail address, age, household income, years of education completed and health questions.

After a couple of screens of this I decided I was giving out too much information and exited the screen. But within an hour we began receiving numerous e-mails about education opportunities, medical supplies, dating services and laptops waiting to be delivered. I tried to unsubscribe to these e-mails, but each day we have 20 to 40 new items in our junk mail to delete. Is there any way to stop all of this?

DENNIS THOMPSON,

PRINCETON, MINN.

AThe sad truth is that you're doing all you can. I could refer you to other anti-spam software at spam-filter-review.toptenreviews.com/, but it sounds as if your spam filter is working.

Spam is a huge problem because it constitutes 85 to 90 percent of all e-mail. Fortunately, good e-mail filtering software will stop most spam from reaching your inbox.

Unfortunately, you're getting more than your share of spam as a result of providing personal information on that form. Trying to unsubscribe to the spam simply confirmed to the spammers that you're reading their mail, making you an even more attractive target.

You should never volunteer personal information except to a website (not an e-mail) that you know and trust. Don't assume a pop-up ad is affiliated with a trusted website.

QYou warned against using public Wi-Fi networks for online banking because of security concerns. Wouldn't the same caveats hold true for my home Wi-Fi network?

JIM RANKIN, WILMINGTON, N.C.

ASomeone could steal your banking information from your home Wi-Fi network. But because the signals are short-range, the thieves would have to be your immediate neighbors or someone lurking near your house.

Wi-Fi signals typically have a maximum range of 300 feet, and the actual distance can be half that, depending on how many walls or floors the signal must travel through. The exception: Newer Wi-Fi routers using the 802.11n standard have more than double the maximum range of their predecessors.

If you're concerned, don't use home Wi-Fi for online banking. Disconnect your wireless router and plug your Internet modem directly into your PC; that wired connection is much more secure.

E-mail tech questions to steve.j.alexander @gmail.com, or write to Tech Q&A, 425 Portland Av. S., Minneapolis, MN 55488-0002. Include name, city and telephone number.