The F8 for start-up option is what you are looking for.
This is normally refered to as the start page or start-up page. Reboot your computer and as soon as it posts the graphics and memory clock speed(the very first thing you see on your monitor) toggle the F8 and keep doing it till you get the start-up page with safemode option on it. If it doesn't come up and your computer boots to windows let it completely launch windows and then restart the system and try it again.keep doing it till you get there.