When an infected program is run, it will search the whole directory structure of the disk and infect almost every COM-program on disk. This takes time, so Omega is easy to find because programs take much more time to load.
Omega won't infect a file if it is marked read-only.
Omega will activate on every Friday the 13th. It then displays an omega-character ('O') and overwrites the beginning of the first two hard disks in the system, destroying the partition records.