These days laptops do not come with a disk at all. There is usually, and this varies from manufacturer to manufacturer, a programme that will burn a set of system restore disks for you. Some manufacturers ahave programmes that allow you to backup your current configuration with installed software and the like.

If you can't find this programme contact either the store you got the laptop from or the manufacturer. You can also check on your hard drive. Ths s frquently partitioned into two, the second partition often contains the backup files (not: you may have to turn on the ability to view hiden files).