It may be that you can't restore your machine to the factory state without the disk. Normally machines like this come with a utility installed which then requires the disk to restore your system drive to the factory state.
For the future, consider buying imaging software like Norton Ghost. These applications create a complete snapshot of your drive (not a file based backup.) They snapshot the drive exactly as it is without "understanding" what is on the drive. You can use the image file they create to restore the drive (or a replacement drive) to the state it was when the snapshot was taken. Very very very handy!!!!!
Matthew
August 2007