Question Computer is powered, but no signal to display plus the keyboard and mouse is not receiving power

[jAhmed12]

My pc spec's ;
Cpu: Amd phenom II x4 965 black edition
Motherboard: Gigabyte 78LMT-USB3 R2
Ram: corsair xms3 2x4gb ddr3 1333mhz
Gpu: Gigabyte Radeon Rx 570 4gb gaming oc
Psu: Evga 500w 80+
Os: Windows 10

Built this last week. when i was using it last night, I only installed the RGB fusion software to change the graphics card colour to white and then i put the computer to sleep. when i pressed the power button this morning there was no signal on the screen but the computer powered on, the mouse and keyboard powered on too. because of this i went looking into my computer thinking there was a problem with my Gpu. However i came across a blinking light on the Gpu and searched up what it indicates, i found that it indicates that there is a 'Abnormal power supply' but people who have had this blinking have said nothing has been affected their pc and it is still working. So i went looking more and tried to follow a video explaining how to fix this issue (link bellow) but the only thing it did was stop the power to my keyboard and mouse. So i am now here....
also i tested the monitor and the wire on my playstation and it worked perfectly fine.
I don't really want to buy a new power supply cuz i'm 16 and i don't have money.

the video ;

View: https://www.youtube.com/watch?v=2RUe5m8Z0MY


EDIT: i changed the battery on the motherboard and the mouse and keyboard are receiving power but still no signal on the display

 

[rgd1101]

take the gpu out and test with the onboard gpu?
exact model of the psu?

 

[jAhmed12]

Its working now, idk how but all i did was change the cmos battery.

 

[madartzgraphics]

Its working now, idk how but all i did was change the cmos battery.

Tell me when the issue came back. The term "Abnormal power supply " can be translated into an unstable power so that means something.

 

[jAhmed12]

The problem came back.
after I fixed it, I used my pc as normal for around a week and then I realised that the hard drive was not big enough so i purchased a 1tb seagate barracuda. My cpu was too old to play apex legends so i decided to upgrade my cpu to a FX 6300. it arrived today and i installed it onto the computer but there was no post like before fans spinning and led on but no post. I placed my old cpu back into the computer... then again no post, even when I changed the cmos battery. Adddition to this i have bought a internal speaker to check if the ram was the problem and it was not. Im just confused to what is wrong with the computer.

 

[jAhmed12]

take the gpu out and test with the onboard gpu?
exact model of the psu?

I took out the gpu and there was no post
The psu exact model: EVGA 500 W 80+ Certified ATX

 

[rgd1101]

EVGA 500 W 80+ Certified ATX

where the model? evga is the brand

 

[jAhmed12]

where the model? evga is the brand

I dont know what you mean by the model but the full name is
EVGA 500 W1, 80+ WHITE 500W, Power Supply 100-W1-0500-K3, Black

 

[jAhmed12]

Also when i hold my reset switch on the case the gpu fans increase in speed, like around 3000rpm (estimation) and sound like a jet engine