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.
9 Comments - Last post 5 minutes ago by OneManArmyStar
1,174 Comments - Last post 6 minutes ago by spodamayn
65 Comments - Last post 2 hours ago by supremeentity
9 Comments - Last post 3 hours ago by OneManArmyStar
54 Comments - Last post 3 hours ago by oldman82
58 Comments - Last post 4 hours ago by nateraade
17 Comments - Last post 4 hours ago by Serale
71 Comments - Last post 49 seconds ago by PlainVanilla
21 Comments - Last post 2 minutes ago by UnbakedBacon
24 Comments - Last post 4 minutes ago by MyrXIII
2,505 Comments - Last post 12 minutes ago by JMM72
1,263 Comments - Last post 1 hour ago by Gelweo
140 Comments - Last post 1 hour ago by samwise84
38 Comments - Last post 1 hour ago by DanielStoSve
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.