why would your computer screen turn black?

This is most likely happening from a screen saver.

Boot into Vista again. Hit control+alt+delete then select task manager. Next go to File>Run>(type this >) explorer.exe hit enter. If it works reboot and see if the problem continues, if not run checkdisk by typing chkdsk C: /r in the start menu. Do NOT use scans from the internet they are bogus and fill your computer with viruses or adware. If the problem continues do the control alt del thing again and access System Restore by going to the Start menu>All Programs> Accessories> System Tools> System Restore. Select a date before your screen turned black and then click the restore button. If it works run the scans as mentioned.

Maybe that's your screen saver or maybe it just turns off on you.

The computer is turned off or the operating system stoped working

Cuz the computer is off.

Cuz it f**ked up on you. or your installing windows XP

cause you just shut it off

complicated thing. query onto google or bing. that will help!

cause it is off