I meant to post earlier, but I was busy.
There did seem to be a pattern.
I was playing a game (mass effect 3 through origin). It was saving, and then is BSODed. Restart to no bootable device. Had to restart a few times, then I got in. Then it froze. I let it sit a while, then it BSODed again. Then it's working. This happened 3 times or so.
I downloaded BlueScreenView, and after some fiddling with the dump file folder location, it seems to indicate that all the errors it finds is due to an issue with igdkmd64.sys which seems to be an onboard intel graphics card driver issue. As such, I've updated that.
Also tried to run memtest86. This laptop has no disk drive, so I burned it to a spare flash drive I had with the imageUSB provided within the download. It seemed to have been burned correctly, but then I couldn't boot from it. Coming back into windows, I noticed that it didn't show up in explorer anymore. Disk management shows it there, but it says "No Media" and lists 0 storage space. It looks like the flash drive has been bricked, so I'm a little wary of trying this with my other, higher capacity drive.
Instead, I ran Window's internal memory test, and it found no errors.
While trying to boot from the flash drive, I did notice that the boot order in BIOS had my HDD listed before my SSD (where the OS is at), so I swapped those two. While the computer has BSODed while playing games since then, it has at least booted into windows. So maybe that helped with not finding the boot location is if was getting stuck on the HDD sometimes?
I have since updated my graphics card directly from Nvidias site since they had a higher driver version than what acer offered. I did have a long gaming session yesterday and no BSOD, so maybe that fixed it?
I don't think so. If it overheats, the computer just usually shuts down and doesn't display a BSOD, right? At least, that's what it did to my last computer.
In any case, I downloaded Core Temp, and while playing, the temp didn't get above 82C, usually more in the low to mid 70s, which seems fine?
But so now i'm wondering if my issues are stemming from the same thing or if I'm just having bad luck and getting hit with multiple issues at once? to recap:
1. A few months ago, my HDD just stopped appearing in BIOS and explorer and I couldn't access it. It reappeared a few days later...
2. Computer often hangs. Maybe every 5 or so minutes it hangs for about 4 seconds.
3. Just recently, computer has been BSODing when playing games, and upon restarting it says "No Bootable Device" and I have to restart like 5 times before I can get into windows. Then it freezes, and then I can get back in again... After updating some drivers directly from manufacturers and reworking the boot order, it hasn't happened again yet...
At this point, I am thinking that a reinstallation of windows might be in order because I just don't know what else to do. At least that would help identify if it's a hardware or software issues.