Multiple problems - Mouse movement and game errors

This has been occurring now for quite some time, but it has been happening even more often recently. As soon as the login screen for Crossfire comes up, the mouse becomes laggy almost, i.e. the movement is not smooth and it makes the game completely unplayable because looking around in game is jerky and you cannot make fine adjustments. This ONLY occurs with Crossfire, and as soon as the game is closed the mouse returns to normal

Also, it seems that 9 out of 10 times that I open Crossfire and join a server, I immediately get a game error of something like file not found...Even on the 10th when it doesn't happen right away, it will usually immediately after completing a game and returning to the lobby.