Apparently, using the disk will overwrite anything you've done with the computer since you got it
I would suggest that you talk to the person at school in charge of selling the computers and see if they can recover your data before you use the restore disks.
http://www.bootdisk.com/bootdisk.htm
You could try booting to a DOS floppy, copying your important files to another drive (e.g. D: ) and using the Restore CD to "Restore First Partition Only" afterwards.
And always remember to back-up your important data regularly.