Answer to: screen won't turn off when closing lidThe screen sleep magnet could of slipped out of place or energy saver could be set to "never sleep". You could also try to reset the SMC---http://support.apple.com/kb/HT3964.
Answer to: DC-In Board cable ripped! Which cable is what?Personally I would not run the computer with a cable ripped. But then again it is your computer and your choice. I would not risk it unless you still have applecare.
Answer to: Why aren't my MacBook Pro's internal speakers working?Hi, I had the same problem, and I resolved it today. I had checked the speaker connections but they were all in tact. I ordered a brand new logic board and put it in today. When I turned on my computer the speakers worked great.