Sounds a lot like Countdown Vampires, but that was a playstation game, no mouse. Also, I don't remember the weaponry on that one, so no idea if you had two guns with laser sights.
More questions on the game. Was it a roleplaying game (ie, levels for your character)? Pure FPS shoot'em'up (Doom, Duke Nukem, or Blood 3d style) or did it have puzzles (Silent Hill, Vampire: The Masquerade, etc).
Are we talking actual late 90s pc-game, or console game in the early 2000s?
Sadly, I don't know if the description (other than the two weapons with laser sights) is distinct enough to define the game from others of the genre.
Did you know the game, or were you needing help figuring out what the game was?