Computer will not start up

Hello,
i recently had a power failure, now everytime i try to turn on my computer it comes up with a message saying windows did not start up successfully. it them comes up with the options safe mode, start windows normally, last known good configuration etc, ive tried everyone n then it goes to the windows xp screen after a few seconds it goes to this blue screen and straight away it goes back to that message saying windows did not start up successfully. i have to turn it off by the switch and when i turn it back on my monitor makes a weird but soft noise