F8 is usually for troubleshooting methods such safe mode last good known configuration. Once you have purchased a copy of windows 7, turn the computer on and hit f10 or f12 to go into the boot menu. You want to select cd/dvd rom to boot from. Your laptop will boot from the disk and go into setup mode. you need to format the drive first and install windows7. Follow the directions and you will have windows 7 loaded in atleast 30 minutes.