Strong virus-checking capabilities plus an easy-to-use interface have positioned Symantec's Norton Anti-Virus (NAV) 2.0 for Windows 95 ($70 street) as a solid upgrade to our last year's Editors' Choice-winning product. Also included is Netscape Helper, which checks for viruses during file downloads.

NAV did well on the NCSA tests, posting perfect scores on the WildList, boot-sector, and macro-repair tests. NAV did not fare as well on performance tests, posting an average time on the total-scan test and among the slowest times on the .ZIP scan-time test. More seriously, its resident guard program cut ZD Winstone 97 performance by 8 percent -- a potentially troublesome level, especially if you run other resident utilities simultaneously. Only the resident searcher in PC-cillin robbed the same number of cycles.

The NAV interface is especially gentle when the scanner finds a virus. The wizard interface and graphics are comforting, and several buttons lead you to additional information along the way. NAV also locates new polymorphic viruses that it doesn't already know. Its scanner sets up a virtual computer that emulates a CPU in code, and this virtual CPU starts to run every executable file. Symantec says that for most programs it takes only a few bytes of code to perform this test, so you shouldn't notice any impact on the scanner speed.

NAV includes a simple dialog that lets you update the virus-definition files over the Internet or Symantec'sBBS. (These files are changed at least monthly and are free for the life of the product.) However, NAV may not always notify you when the definition file is out-of-date, so you have to remember to update it regularly.

You can easily set up a scan of one or more local hard drives. But if you want to scan specific files, directory branches, or network drives, then you have to scan one at a time. This requires navigating through several dialog boxes. Overall, Norton Anti-Virus remains one of the strongest products in this category, but its competitors are definitely gaining ground.