If the window is black at the start, then you have messed up some mods.
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Be sure you meet the requirement, especially...
Software Requirements:
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Uninstall java.
Install 64-bit java.
Reinstall MC, make sure you have no mods/texture packs.
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Do you have more than one monitor? What OS?
It looks like you have more than one monitor from the video. Try unplugging all but one, reboot, and try it.
Also, run it in a terminal / command prompt, post the output on pastebin, and link it here.
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This has happened since I got a new pc and whenever I open minecraft it just goes black and makes my pc really laggy and slow for about 2 minutes. Can anyone help?
Here's a video showing it: https://www.dropbox.com/s/pfi9thtv1kwwtj8/20131109_195450.mp4
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