restoring dell pc windows vista?

i always used the control shift f11 key combos and it would always work. but now they are saying to do the f8 when the dell logo comes up and then another screen pops up where i am supposed to choose repair computer or something like that but the option to go to that screen doesnt come up on my computer. what am i doing wrong!

and i dont need the discs and what not to restore anything, i just use the computer as my gaming sims computer and i have all the pics and stuff i need already saved onto my mac.

i went to the link that you provided (thank you) and it says about clicking on repair your computer which should be above safe mode. when that screen comes up for me i do not have the option to click on that.

yikes. how exactly do i fix that? or is there even a way to do it.