E-mail and newsgroup spam are annoying, but at least they file neatly into your e-mail or newsgroup reader. Pop-up Web ads, on the other hand, erupt onto your desktop as new windows -- sometimes multiple windows -- disrupting your Web browsing, wasting system resources, and taking over your screen. Hoag Levins, editor at AdAge.com, the Website of Advertising Age, says pop-up ads are "widely detested, but a certain percentage of people will remember that awful pop-up ad they saw and remember the product. It can be effective but leaves a bad taste." Spyware is even more insidious. Seldom seen at all, spyware takes information from your system and invisibly passes it back to the spyware's owner. One form of spyware is embedded in Websites or in Web-style mail and is usually limited in the kind of information it can collect, especially if your Web security settings are high enough. The other type of spyware is installed on your computer with programs and gathers information from your computer and sends it out through internal pipes without even going through your e-mail program. Andrew Ryan, CEO of ARC Solutions Inc., a Washington, D.C., engineering firm (www.arcsolutionsinc.com), says spyware is costly to businesses. "It's a security risk; many businesses don't know how to control what information goes out," says Ryan, who notes that hackers can exploit the adware or spyware program intended to transmit simple marketing data. "Spyware can be turned into a Trojan horse," says Ryan. "It takes about 15 to 20 seconds to crack user passwords in the (Windows) registry." Even with innocuous information going to marketers, thousands of users sending the information can slow connections. "If a company doesn't know what it's doing, it will throw money at more bandwidth," says Ryan. He says he'd rather see companies get expert help to lock down the network. Thankfully, pop-up bashing software is plentiful, with varying rates of success. The kinds to avoid are programs advertised through spam e-mail or passed on from a friend who got it from a friend. Good companies don't send spam -- and nefarious code is often spread by spam or passed from one naive user to the next. Head straight for Tooto Technologies (www.tooto.com) and try Zero Popup 6.1 free for two weeks. The program loads and unloads automatically with Microsoft Internet Explorer (IE) 4.0 and above, and Windows 9x, 2000, ME, NT, or XP. With Zero Popup, you'll be saved from pop-ups, banner ads, floating ads, and Windows messenger spam. Priced at $24.95, it will also let you instantly clear Web history including cookies and auto-completed forms and passwords and even blocks ActiveX spyware from the Web. SLAY SPYWARE, PRESENT AND PAST If you don't believe your computer is allowing programs to phone home, get a software firewall such as ZoneAlarm Pro (www.zonealarm.com) and see the alerts as the program works. The firewall can deny any program permission to access the Internet, but to get rid of those spy components, try Ad-aware 6.0 by LavaSoft Sweden (www.lavasoft.de). While Zero Popup kills pop-ups for a living, and makes a hobby of killing ActiveX Web spyware, Ad-aware deals with spyware full time, including the snoopers that come with installed programs. Ad-aware immediately found eight pieces of tattletale software on our brand new computer -- all placed there by "legitimate" vendors, not criminals. (You may have to keep some "adware" if you want to run free programs that require it.) Ad-aware finds tattle-ware by using a database of known snoops. Just click to update the database free before you run it each time. For constant protection from adware, spyware, key-loggers, selected Trojans, and even pop-ups, pay $26.95 for Ad-aware Plus. Gary Stein, advertising analyst for Jupiter Research, says online advertising is so inexpensive, people probably aren't even thinking about what they're doing. "Consumers tend to find pop-ups even more intrusive than spam. As soon as they wise up, these things should go away."