This virus is believed to have been written by a student at the "Vish Finansovo-Stopanski Institut" in Bulgaria. It can be stopped by making files read-only. When it activates, it may display the following messages.
HELLO!!! HAPPY DAY and SUCCESS from virus 1.1 VFSI-Svistov
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 scanning & removal options
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.