wow cursor stuck after switch from ati to nvidia

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hey, i recently just switched video cards. noticed a few problems in different games but fixing one by one. anyway, in wow for some reason at the log in screen the mouse works for a few seconds then gets stuck. the computer isnt stuck but only the mouse. i have to disconnect the mouse and reconnect it to get it moving but even then i have to log in quickly or it will get stuck again. once im in the game its ok though. anyone know whats wrong?