Need Help Troubleshooting if Mainboard is bad or PSU

[MadMan2415]

Computer Specs
MSI 970A-G43+
AMD FX-4300
2xMushkin Essentials DDR3 996769 4gig 
NVIDIA GeForce GT 730
1tb Western Digital SATA HD
Corsair CX500 PSU (website says 500 watts but not sure myself as it was given to me)
No CD/DVD Drive
No Overclocking
Windows 7 64bit ultimate

My computer is showing 3.95 gigs of memory available out of 8 gigs installed in the windows system window . All 8 gigs show in Bios and in Cupid Cpu-z but Windows Resource Moniter shows the missing memory as hardware locked. I have done the usual trouble shooting-
msconfig -->max memory unchecked
updated all drivers

updated BIOS
checked both sticks independently with Memtest86 for 48 hours each stick and each slot no errors detected
checked both sticks independently with Memtest86 for 48 hours each stick in a different computer no errors detected
checked slots on the computer having issues with a different memory stick no errors or issues (only have 1 extra stick so couldn't check with the full 8 gigs installed)
HD Checked for errors
Stress tested computer 48 hours no issues (with the memory issue but not sure on how to fix it to stress test without the error)
Complete tear down clean rebuild and reseat of all components and cables
Increased voltage to Memory in .05v increments (only from 1.5v up to 1.6v as being unsure on max voltage before damage got nervous and stopped)

looked for memory mapping in my bios as I have seens some posts online point to this as a fix but can not find any kind of option to enable memory mapping

I am at a loss for what is causing the issue. The memory issue just started randomly with no hardware or software changes. Thinking I might have a PSU issue as it is the only thing I didn't buy new it was given to me by a friend who pulled it when he upgraded his pc. I guess the question is can a bad PSU be causing the issue, am I missing something troubleshooting , and if it is the PSU what should I replace it with? I have tried many PSU calculators and what they are reporting I should use just seem way under what is expected. If it is the Board what would be a good repacement that would work with the current components?
Any help and or advice is appreciated.

 

Edited November 30, 2017 by MadMan2415
Added Photos

[comicsansms]

When you press the Windows key and "Pause Break" key, does it show that you have a 32bit or 64bit version of windows

 

This is where it would say that.

[MadMan2415]

It shows 64 bit. Sorry added screenshots of Resource Monitor, System Info , and Cupid CPU-Z Memory tabs to the original posts

[MadMan2415]

So added 1 more 4 gig stick and the only thing that change was everything showed 12 gigs installed and 3.95 available. So the extra 4 became hardware locked also.