Battery dissapearing/reapearing with an X in the battery symbol
I recently replaced RAM, Hard Drive and Battery in my MacBook Pro (late 2011) model. I'm now having issues where the battery disconnects and reconnects at random times. I can see this happening as the battery turns into a battery with an X inside, and then back to a regular battery charging symbol. When the computer is put to sleep by shutting the lid, sometimes it just won't wake no matter what combination of keys and power button I try. Occasionally the cursor gets hijacked, for lack of a better word. It becomes jittery and jumps around the screen.
When I opened up the machine there was a screw missing from the original battery (there was only one of the two screws in place). Can I get replacement screws? Is that (a loose battery) likely the cause of my issues?
I've done a PRAM/NVRAM and SMC reset, but that hasn't seemed to do anything. I've also cleaned the track pad after some advice from the internet saying that might have been an issue.
Is this a good question?