What's wrong with my computer?

The other day I moved my computer on its table with wheels,since then it will no longer boot up, it was not running at the time, now when I turn it on I get the Windows start up page (black with the windows 4 colour flag and the blue line that moves) then after a couple of minutes I get a black screen with white lettering stating that the CD drives are OK, the RAM is 533 Mhz and that the hard drive is a Samsung 250 go a few minutes later I get another black page saying to start up in last good configuration etc but it never starts up, no matter white message I choose it always comes back to the same black page