Really bad computer problems.

This could be alot of things causing this so first we need to narrow down what exactly is causing this problem first things first are you able to boot into safe mode?

Also if at all possible when the computer going into the BSOD are you able to get the crash code from it for us?(assuming its windows 8, 8.1, or 10)

After we get this we will move onto the next steps to fix the problem or atleast figure out whats wrong!

Please post your full specs.

At 6 years old, there's numerous potential causes. Anything from a corrupt OS to failing hardware.

Can you boot to safe mode? Do you get any error codes? I assume you use an anti-virus/anti-malware program?

If your OS is corrupt (or bogged down from viruses), a clean install is easy. Backing up anything you want to save takes time though.

CPU/Mobo/RAM are fairly resiliant, but losing display can potentially be caused by a failing GPU, PSU or HDD - all of which are (relatively) easy fixes.

The reset button not working unless you wait a while leads me to think it's related to power, but there's always potential it's motherboard related.

Without the full spec, it's impossible to get a true feel for it.

when a good power supply fails in one of its power outputs, it sends a signal to the motherboard that tells the system that the power is not ready. The motherboard responds by not allowing the CPU to start. (you get a blank screen, but the fans turn on)

sometimes a power supply will fail when it is warm but not when it is cool. I would test the voltages on the power supply and make sure they are ok.
maybe get into bios and check the voltages if your BIOS has that function. Test with a different power supply,
check the outputs 3.3V, +5v, +12 volt and -12 volt one may be wrong

Summary

This is a general procedure on how to find and upload the files we need in order for us to help you repair your computer.

Details

When your computer crashes with a Blue Screen Of Death (or BSOD) the events leading up to the crash are held in memory until you restart your computer, when they are written to a file (called a DMP file). This file is critical in our diagnosis

How to find and upload the files to us for analysis.
There are 3 files that will help us find out what caused the crash. The DMP file, the output of MSinfo, and your computer specifications. IF you cannot boot in normal mode try safe mode. If you still cannot boot let us know

If your computer cannot boot normally you may be able to get the files by booting into safe mode (often F8). In win 10 you may have to try this method

You can get into safe mode on a non booting computer by starting the boot and holding down the power button for 5 seconds to stop the boot and turn off the computer. Do this two times and on the third attempt you will be given advanced options including safe mode

The sequence to get to the boot options that way (interrupting the boot twice), Advanced options > Troubleshoot > Advanced options > Start-up Settings, adjust settings, click restart

If you are overclocking (pushing the components beyond their design) you should revert to default at least until the crashing is solved. If you dont know what it is you probably are not overclocking.

The procedure for finding and uploading the DMP files:
Navigate to C:\Windows\Minidump and drag the contents to your desktop. If the minidump folder is not there or empty there may be a larger DMP file located at C:\WINDOWS called MEMORY.DMP which we can also use.
Zip up the files using the built in compression on win 8 or winzip/winrar on other operating systems. We prefer the 3 most recent DMP files but if you have less we can still look at them. We can not use DMPS more than 30 days old as the current issue may be different and we do not need more than 3
Upload them to a file sharing service like OneDrive or any other file sharing service and put a link to them in your reply.

Link for how to upload the DMP file is here

The procedure for running MSinfo32
Go to start>run>MSinfo32>enter (this varies by OS)
Go to "file" "save" and upload the saved file with the DMPS

System specifications are also useful so include them if possible. You can use an application like Speccy, AIDA64, etc.

Troubleshooting
If there is no "minidump" folder, or if the folder is empty make sure "minidumps" are enabled.

To ensure minidumps are enabled:

• 
  Go to Start, in the Search Box type: sysdm.cpl, press Enter.
  (In win 8 you can use the windows key "win" + "s")
  Under the Advanced tab, click on the Startup and Recovery Settings button.
  Ensure that Automatically restart is unchecked.
  Under the Write Debugging Information header select Small memory dump (256 kB) in the drop down box (the 256kb varies). If you are on win 10 use "automatic memory dmp"
  Ensure that the Small Dump Directory is listed as %systemroot%\Minidump.
  OK your way out.
  Reboot if changes have been made.

If minidumps are still not being created check these reasons as to why that may be happening
For dumps to be produced The following should be correct

• 
  Page file must be on the same drive as your operating system
  Page file base allocation size must be greater than installed physical RAM
  Windows Error Reporting (WER) system service should be set to MANUAL
  Set page file to system managed on the OS drive
  Set system crash/recovery options to "kernel memory dump"
  User account control must be running.
  Sometimes SSD drives with older firmware do not create DMPS (update firmware)
  Cleaner applications like Ccleaner delete DMP files so dont run them until you are fixed.

Bad Physical RAM may prevent the data from being saved and written to a file on reboot. If you suspect bad RAM run Memtest from this wiki

Full memory dumps can also be deleted (in win 7) if your HD space is under 25 gigs but if you configured your system as the above suggests you should not be generating full dumps.

If you receive the message "Access is denied" or "file not found" when dealing with the DMP files you will need to take ownership of them
Follow these links.
http://www.thewindowsclub.com/take-ownership-windows-8
http://windows.mercenie.com/windows...-permission-of-a-file-or-folder-in-windows-8/

If you still are having a problem create a folder on your desktop>copy the files into it>compress the folder (ZIP)> upload it to your Onedrive and put a link to it in your next post.

folder does not look like there are any files.
you might want to create a kernel memory dump of the correctly running system
google "how to force a memory dump using a keyboard"
and make the registry settings, then reboot and force a memory dump when the system is ok.
I can look at the drivers and hardware for certain problems.
overall, it sounds like a hardware problem that would be in your power or power regulation circuits.
-make sure you blow out any dust from the PSU, CPU, and GPU fans. dust build up can make a fan spin slow or stop.

do you ever get jumbled text while in BIOS before the system has given control to windows.
(it can indicate a GPU failure or overheating of the GPU as well as incorrect voltages to the GPU)