High Memory Usage, and Windows Startup Black Screen

[ItsOpenMikeNight]

Forgive me, I am a novice when it comes to the computer. Its showing that I have high memory usage in the task manager and my computer is noticeably running at a slow rate. Another point of concern is that in the task manager it shows I have 16gbs of ram when I actually have 24. I've ran CCleaner, and malwarebytes. It is still showing that I am using 90% of my memory.

The next problem is on startup. I end up with a black screen and just a mouse on it. After that my monitors go to power-save-mode like there is nothing being input to them. If I am lucky after a ridiculous amount of time and If the monitors don't get stuck in Power-save-Mode the Windows
login loads.

Specs:

Operating System:
Windows 10 Pro 64-bit
CPU:
Intel Core i7 980 @ 3.33GHz
Gulftown 32nm Technology
RAM:
24.0GB Triple-Channel DDR3 @ 533MHz (8-8-8-20)
Motherboard:
ASUSTeK Computer INC. Rampage III Extreme (LGA1366)
Graphics:
VA1912wSERIES (1440x900@60Hz)
DELL S2340M (1920x1080@60Hz)
2048MB ATI AMD Radeon HD 7800 Series (XFX Pine Group)
Storage:
931GB Seagate ST1000DL004 HD105SI ATA Device (SATA)
119GB Crucial C300-CTFDDAC128MAG ATA Device (SSD)
Optical Drives:
ASUS DRW-24B1ST c ATA Device
Audio:
Focusrite USB Audio

 

[Lutfij]

1| Have you made sure your motherboard BIOS is up to date?
2| When in BIOS can you see if the motherboard detects all 24GB of your ram?
3| See if a repair install changes anything for you.
4| You may need to recreate your bootable USB installer and reinstall your OS if repair install doesn't work for you.