I feel for you Veronica but at least you were not one of the unfortunate souls affected by the Vista Black Screen of Death. There are apparently several different scenarios in which you boot only to a black screen with a movable cursor (all boot options end same way). I have seen a few of these and as you cannot boot from CD and do a repair install with vista it means you are in backup/wipe/reload land. There are some fixes around but only for certain problems which have not corresponded to the ones I have come across.