The 640 byte variant contains the text
(C) MPS-OPC 1991 v3.1
but the 654 byte one claims to be version 3.2. Not yet analyzed.
Based on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the detected program or file, or ask you for a desired action.
Find the latest advice in our Community Knowledge Base.
See the manual for your F-Secure product on the Help Center.
Submit a file or URL for further analysis.
A 469 byte version.
Probably the first version - 376 bytes.
This virus is structurally different, and belongs to a different family, as it only infects .EXE files, but it is probably written by the same authors.