i have a compaq presario c551nr laptop. it came shipped with vista, and i trashed the heard drive about a year later. so now after trying to get mac os x and ubuntu to work, i have cloned the current computer that i am posting this with. this computer that i am using has win xp, and i cloned it. it was working for about a month with minor system errors, now it wont boot. what happens is i push power, and nothing happens. i can hear the fan and hd running, but the screen doesnt even flicker. its dead. so i suddenly remembered that i have system restore discs for win xp and vista, and i could try those, but theyre system restore, and thats difficult to handle. so is there a way to force the computer to boot from a cd or junk drive? or a key combo to boot it?