99 D'elegance head light not working

I have a 1999 deville elegance my wife left for work yesterday and the headlights where not working i have checked the fuses they are all good and this is confirmed by the fact that the other things that run on the same fuse work. Im going to check the headlights tom during the day but i find it unlikely that all 4 bulbs blew out at the same time when she shut the car off they worked when she came home then when she went to go back to work they didnt work anymore any suggestions on what it might be i have till friday night to get it fixed