Surfing the Net without some level of security has become like driving in NASCAR without a seat belt.

Some users deal with this by cobbling together a set of different security utilities, but Symantec Corp. and McAfee.com Corp., the Pepsi and Coke of the computer-security business, take a different approach with two new all-in-one suites. Both combine anti-virus protection, firewall software, pop-up ad blocking, parental-control Web screening and spam filtering.

As ever, the most important reason to buy any PC-security utility is virus defense. But after years of tough competition, these two contenders have battled their way to parity -- both proved equally effective in our tests, including one of a custom-made virus that wouldn't appear in either program's database.

The differences between the Symantec and McAfee programs all surface in other areas.

Symantec's Norton Internet Security 2003 (Win 98 or newer/Win 2000 or newer, $70) is particularly strong in its parental-control options. It allows you to set up different user identities, each with a password-protected access level of child, teenager or adult, and can then prevent selected users from so much as e-mailing a street address or credit card number.

But Symantec's Web screening goes a little too far -- it prevents children from viewing the likes of Playboy and various adult film stars' Web sites, but it also restricted The Post's Web site. It didn't explain why it blocked any of these places, and customizing its blocked-sites list is one of the more difficult things to do in the entire Norton suite.

Norton's pop-up ad blocker, by contrast, kept my Web browser pop-up-free without disrupting normal use. The included firewall offers the intriguing bonus feature of a map showing the location of whatever computer program is trying to break into your PC. And its spam filter -- a feature that costs $29 extra in the McAfee suite -- gets updated along with its anti-virus engine, which seemed to help its efficiency on my test PC: The daily dose of spam went from 30 junk e-mails to three, without the loss of any legitimate mail.

McAfee's Internet Security 5.0 suite (Win 98 or newer/Win 2000 or newer, $90) was a bit more difficult to install than Symantec's entry. I had to click "yes" more than 40 times because the suite's drivers are not digitally signed, something Windows XP loathes. And setting up user accounts with the program required me to manipulate Windows' systemwide add-a-new-user interface, which can be daunting for newcomers.

Once up and running, though, McAfee's suite offered easier access than the Norton bundle to many of the same features. McAfee's parental control is easier to live with: When a child comes to a blocked site, a warning appears, saying that an adult user needs to verify that the site is okay to visit. The adult user can then enter a user name and password to learn why the site was blocked before deciding to allow it.

The McAfee suite also keeps you informed on what its "Browser Buddy" catches, showing how many cookies, pop-up ads, "Web bugs" (invisible graphics that can track your Web use) and so on are being blocked on each Web page. And it never missed a pop-up ad -- yes, even at The Post's own site.

Technical support for both companies was adequate, with a shorter hold time at McAfee (two minutes, vs. five at Symantec). Unfortunately, both levy steep charges for this help -- $4.99 a minute at McAfee, $2.99 at Symantec, or $39 per incident at either company.

Which to buy? The Norton suite packs in more tools, but the McAfee suite is friendlier to its user after that cumbersome installation. If McAfee's software ever shows up pre-configured on new PCs (or the company updates its installer to play nice with Windows XP) the choice could be easier. In the meantime, if you want more features -- in particular, spam filtering -- and a finer degree of control, then Norton is the choice. If you'd rather keep things simpler, go with McAfee.