hmm, if u do have an official installation cd
and if u can, jus format the entire hard drive if u can reach tht stage, n try re installin from there.
and u shud chnge the order of boot priority to d cd
disconnect the internet and also unwanted HDD's or other CD roms..
also, chk the RAM's.. jus remove and re insert them, to chk if nythin is wrong.
since it is a lappy it might b a bit complicated to open up, but it is for the best
hope u solve it soon n get ur system up and runnin soon