If the window is black at the start, then you have messed up some mods.
Comment has been collapsed.
Be sure you meet the requirement, especially...
Software Requirements:
Comment has been collapsed.
Uninstall java.
Install 64-bit java.
Reinstall MC, make sure you have no mods/texture packs.
Comment has been collapsed.
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.
Comment has been collapsed.
1,814 Comments - Last post 31 minutes ago by moronic
4 Comments - Last post 36 minutes ago by wormmayhem
43 Comments - Last post 2 hours ago by BorschtLover
58 Comments - Last post 4 hours ago by SketCZ
85 Comments - Last post 4 hours ago by WaxWorm
16,299 Comments - Last post 8 hours ago by Carenard
72 Comments - Last post 18 hours ago by Reidor
26 Comments - Last post 2 minutes ago by Gamy7
9,534 Comments - Last post 8 minutes ago by Noxco
1,598 Comments - Last post 11 minutes ago by Fluffster
807 Comments - Last post 11 minutes ago by MyrXIII
186 Comments - Last post 34 minutes ago by himalaya
54 Comments - Last post 58 minutes ago by NoYeti
10,791 Comments - Last post 1 hour ago by WaxWorm
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
Comment has been collapsed.