black screen at startup

"disk0s2" is your filesystem ID. Sounds like a corrupted system. Try starting up from your original system installation disk by inserting the disk and restarting holding down the "C" key. Go to the second screen pull down menu to Utilities > Disk Utility. Select your hard drive in the left hand column. Run repair Disk till it runs clear then run repair permissions. If this fails, please give us the last three figures of your serial number (located on the bottom of your stand).