No Battery Available I have a MacBook Pro 15", early 2011. Earlier this week, I brought it home and plugged it in, and there was an X through the battery. Did an SMC reset, and it started charging again. The next day it stopped again, and the message in the menubar said "No Battery Available." I opened up System Information, and under Power it said there was no battery installed. 

Did another SMC reset and System Information was unable to load information for Power. I recently did another SMC reset, upgraded to Yosemite, and am still getting the no battery available symbol. But now this is what's showing up in System Information:



Is my battery completely dead? Is there any way to recharge it, or do I need to replace it?

UPDATE: I forgot to note, I did an AHT on the machine a couple days ago, and it said there was nothing wrong with the hardware. If the battery was jostled loose, wouldn't AHT flag it?
You probably knocked the battery connector out. Here's a link to a repair guide to replacing the whole battery, which is more than you need. Do steps 1 and 2 to open your computer up, and then make sure the battery connector in Step 3 is 100% plugged in. If it's fully plugged in and it's still not working, the battery itself is probably shot.