This is a simple virus with an uncommon activation routine: on some machines, it turns the the BIOS boot-up password on and changes the password to 'monica'.
Do not confuse this virus with Monika.686, which is a totally different virus.
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.
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See the manual for your F-Secure product on the Help Center.
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