Why would my keyboard not work until i click on device manager and then it works


Jul 18, 2011
Have an acer 5538 that keyboard would not work, got tech to fix, he reinstalled windows and got to user and pass word and it would not type, will work in bios. So he could not do anything, I took home and in frustration i started pressing all the keys and i got past the log in and was able to finish loading windows vista 64 honme prem. Now keyboard still does not work UNTIL I open up device manger(thats all i do, dont have to press anything else) get out of it and voila keybord works perfect?????? Why is this????