does the laptop have a cd/dvd drive? what year is it? if it has dvd drive turn it on hit f8 or f2 what ever it is on your machine. then make sure that it is set to boot from dvd drive 1st not hard drive. then you can use to reinstall windows. if you dont have dvd drive. you can also use your other puter to create a boot from usb flash drive yes it works like a start up disk on usb then. make sure you have usb 1st boot, dvd 2nd boot set in bois. im sure you can find many videos on this topic on youtube on how to boot from usb and so on. cause if you already have a windows 7 disk and cd key all you have to do is get your bois to boot from cd or flash to get it into recovery. other ways is going into dos and typing in the commands for recovery