Go to your start menu, all programs or programs, accessories, system tools, system restore. This will undo any changes you may have done accidentally. You want to choose the date you remember last using your camera. The date will usually be highlighted if system changes were made. This will not undo any files you've saved. You can always undo the system restore if that doesn't work.

If u deleted it just use the windows restore sytem option , or download the driver of what ever it lost at acer