Frequent RSD past several months (2011 Macbook)

2011 Macbook 15"

So about 6 months ago, I started having trouble with my hard drive. At least, that's what Apple told me. Computer RSD'd and was never able to boot back up fully, so I bought a new hard drive and installed it myself. Worked for a day or two, then the same issue happened again. Apple says my hard drive failed out of the box. Take it to get it fixed, it miraculously boots up when I'm trying to show them the problem, works fine for several months.

Then, about 3 months ago, I start getting RSDs when I move my laptop while in use. Not every time, but often. Several times a day. I was out of the country and so was unable to address the issue until now. After shut down, normally it doesn't acknowledge the battery, so I must hold down the power button for 10 seconds, continue holding it down while I plug it in, and continue holding for 10 more seconds. Then it will turn on, but the fans are running on high and the battery is still not being found. So I must then shut down normally and reset SMC. Then it usually turns back on, until the next RSD when I need to repeat the process.

Any ideas?