I have a hp compac nx9030

recently its been playing up in a big way... today I formatted the HD using the windos XP Pro recovery disc thingy and now when it starts up it takes forever to get running I have a blank screen for a while then have a load of little vertical lines at the bottom of the screen which gradually fill up with a counter bar thing....

whats wrong? I had suspected a faulty HD but surely it wouldnt have formatted and installed xp properly if this was the case?