This is a family of stealth multipartite fast infecting viruses originating from Australia. There are at least five variants, sizes ranging from 2 to 3 kB.
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.
One of the variants generates an endless loop to the partition table, making PC crash when it tries to boot from a clean floppy which has MS-DOS v4.0 - 7.0. To overcome this, use PC-DOS 7.0, MS-DOS 3.3x or a non-DOS boot floppy. Contact F-Secure anti-virus support for further instructions.
Note: Rainbow is also an alias for the WordMacro/Colors virus.