With Aldus Corp having to recall an estimated 5,000 copies of its Freehand program after it found they had been infected by a virus program, the problem of those malicious little pieces of code is being taken very seriously indeed. But CD-ROM publisher Lasertrieve Inc of Metuchen, New Jersey claims to have an answer, reports Newsbytes, in the shape of Viralarm, inoculation software that checks that a program has not been infected since it was last run. If it detects changes, it sends a warning message and will not let the infected software run.