It's a lot easier to restore your laptop if you have the OEM restoration CDs but if you don't have them, you can always try the long approach. That is, manually install the OS, then install any missing drivers and then install any programs that you use. Despite it's the long way, it's also the better way since you don't have to deal with any crapware that come bundled with OEM restoration. You can download Windows 7 legally from digital river (just do a Google search for "digitalrivercontent windows 7 download" and you will find links to download the ISO of your OS. Again, this is a 100% legal download provided by Microsoft. For activation after installation of the OS, you will have to use the product key from the windows sticker of your laptop, so it's critical that you download the same version of the OS that your sticker say it is or it won't activate. For device drivers, visit manufacturer's support page.