This is a Visual Basic Script worm that disguises itself as a Valentines Day game.
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.
It is written to spread to all addresses found in Outlook's Contacts folder. It sends e-mail messages that look as follows:
Subject:Are you [User's name] my valentine? Body: Hi [User's name] my valentine, remember me? I ain't seen you in ages! Anyway, check-out and play the attached guess-the-number-game to guess who I am. See you soon, bye-bye! Attachment: GuessGame.html or GuessGame.vbe
Where the attachment GuessGame.html is previously saved in Desktop, My Documents or Temporary folder. If this file does not exist, Numgame sends another copy of itself (GuessGame.vbe) previously saved in Windows System folder.
The worm shows several message boxes trying to play a game with the infected user.
Numgame searches in particular folders and tries to delete several files from the infected computer and from all network drives.
It also changes the system date to 04-08-1981.
F-Secure Anti Virus currently detects Numgame by the heuristics.