A lot of people had problems with the controls. Eventually it was patched, which added a sort of point-and-click, but it wasn't designed as point-and-click and some parts of the game don't work well with the controls.
If you check user reviews at GOG and Steam, some reviewers mention disappearing mouse cursor, even when they have the recommended specs.
Maybe there is a trick to getting the clock to go to 5 with these controls. Hopefully someone can help. Hints forum might be a better place to ask since it sounds like your game is functioning as well as it does for anyone.