Alienware M17x R4 Error codes: 141 and 187 and 8 Beeps

MERGED QUESTION
Question from metalalex : "Alienware M17x R4 Error codes: 141 and 187 and 8 Beeps"

I'm having a problem with my computer giving me the error codes 141 and 187. To give a little more context, the problem first started back in 2013 when my computer started show a black screen right after the Alienware logo. I remember fixing the problem temporarily by moving the display to a different angle (and rebooting), or by connecting a monitor (the lcd screen would turn on after connecting it to a monitor).

However, I decided to upgrade it from windows 7 to windows 10 like a week ago. Right after upgrading, I started noticing that windows was hanging on and off for a couple minutes every now and then. Naturally, I thought it was a driver issue, I found different solutions, but none worked. Thus, I decided to do a clean install of windows 10. After I reinstalled it, I also cleaned up my computer (it was too dusty and temperatures were high), I cleaned up the keyboard, fans, and the heat sinks with a duster and isopropyl alcohol, then I proceeded to clean and replace the thermal paste on the graphics card and the CPU. I built all my computers (except for this one) so i know the proper procedures and precautions to properly clean a system.

Unfortunately, after everything was done and the laptop was turned on, It suddenly turned off when i took it off the counter to place it on my desk. I'm sure I placed everything back carefully and correctly. So right after turning it on again, I went into the BIOS and performed a diagnostics test, every thorough test passed. I resumed using the computer and it turned off again, this time giving me a loop of 8 beeps right after turning it back on, no screen display, nothing.

I decided to call dell just to find out that 8 beeps means that there is a problem with the lcd. They advised me to drain the power from the laptop by unplugging it, removing the battery, and holding the power button for 20 secs ( I held it for 40 secs just in case). Unfortunately, that didn't seem to work. I also tried replacing the graphics card carefully and nothing. I tried to look for damaged ports/parts and couldn't find any. Again, I'm sure I didn't do any physical damage (cleaning and re-pasting is simple).

Surprisingly, I ended up trying to turn it on yesterday after draining the power again, and it did. I performed another test, all passed. However it keeps on rebooting randomly, especially when I move it (even if I don't move it and just type on it, it resets sometimes). And in some cases after it resets the screen wont turn on (no 8 beeps anymore), and connecting a monitor wont fix it either. The laptop still hangs, yet it's still usable. (I'm typing this on the laptop)

Basically I don't know what to do anymore, I don't know how to fix the black screen problem, and the hanging problem. Why does my laptop make 8 beeps sometimes regardless of the successful testing? I tried placing the LCD cable again and no fix. Also, why does my laptop reboot randomly after typing or moving it? Any help would be very appreciated since I cant send it in for repair. I'd like to do it myself due to the cost.

Here are my Specs:

OS Name Microsoft Windows 10 Pro

Version 10.0.17763 Build 17763

System Model M17xR4 3D 120hz

Processor Intel(R) Core(TM) i7-3740QM CPU @ 2.70GHz, 2701 Mhz, 4 Core(s), 8 Logical Processor(s)

BIOS Alienware A14

RAM 16.0 GB

NVIDIA GTX 680M

Here is more info from the reliability history:

Problem signature
Problem Event Name: LiveKernelEvent
Code: 187
Parameter 1: 1
Parameter 2: 0
Parameter 3: 0
Parameter 4: 0
OS version: 10_0_17763
Service Pack: 0_0
Product: 256_1
OS Version: 10.0.17763.2.0.0.256.48
Locale ID: 1033

Problem signature
Problem Event Name: LiveKernelEvent
Code: 141
Parameter 1: ffff9c81ad7e4220
Parameter 2: fffff8005fbabc3c
Parameter 3: 0
Parameter 4: 424
OS version: 10_0_17763
Service Pack: 0_0
Product: 256_1
OS Version: 10.0.17763.2.0.0.256.48
Locale ID: 1033

Both shown as hardware problems.