I have an old laptop with Windows 7 on it. I do not have an installation disk, but I do have the serial number for the OS. I need to make a boot disk/USB because the computer is not starting. All I could find on this site is instructions to make a boot disk using the computer, which is not possible. If it came preinstalled:. Here are the Key/s to press at Boot to reinstall the operating system (new condition). Under each Manufacturer in the list below are the instructions in the respective links for you to follow on how to use their Recovery Partition. Acer – Press Left Alt + F10 Keys. Advent – Tap F10 until Starting System Recovery appears. Asus – Press F9. Dell – Press F8 which will bring up Advanced Boot Options http://www.dell.com/support/troubleshooting/us/en/19/KCS/KcsArticles/ArticleView?docid=DSN_362066. eMachines: Press Left Alt Key + F10. Fujitsu – Press F8. Gateway: Press Alt + F10 Keys - As Acer owns them: press Left Alt + F10 Keys as per Acer eRecovery. HP – Press F11 repeatedly. Lenovo – Press F11. Packard Bell: Press and hold the ALT key while pressing repeatedly the F10 key. Release the keys when a message displays that Windows is loading files. Samsung – Press F4. Sony Vaio – Tap F10 until the Edit Boot Options screen is displayed. Toshiba – Press 0 (zero). If preinstalled, you can also contact your Laptop/Computer Manufacturer and ask them to send you a set of Recovery Disks. They should do that for a small cost, IF they still have them available (Most don't). You can also borrow the exact same edition of Windows 7 Retail DVD and use your Product Key on the COA sticker to reinstall the operating system. Or you can use this for preinstalled OEM or Retail Licenses. Download the correct ISO file and make your own disk and use the Product Key that is on the COA Sticker.