PC Is Working But Doesn't Post !!! Help

[ChrisTsall99]

Hello,
I got an old system
running windows 10 home
cpu:athlon x2 4200+
ram:4x1gb sticks ddr2 677Mhz
psu:coolermaster g650m
hdd:wd caviar blue 1tb
gpu:saphirre r7 260 1gb
mobo:ga m55plus s3g(i am not sure)
So came back home and tried to open my pc it posts and when it get me to the screen that i must set the password it stop posting so i turn it off from from the button and tried to open it again...now i am not seeing anything it doesnt posts at all but i can hear that it is worikng ..i close it and open it again sometimes i am able to see the boot screen and some other times the windows 10 lock screen but it is stop posting after seconds
HELP
SORRY FOR MY BAD ENGLISH

 

[R_1]

open the case (follow proper grounding procedures: http://www.wikihow.com/Ground-Yourself-to-Avoid-Destroying-a-Computer-with-Electrostatic-Discharge ) and remove and inspect the video card, look for signs of overheating (sticky fan, swollen capacitors, heavy dust accumulation).
while the card is out move the video cable to the onboard port on the motherboard and try to boot the system using the iGPU (nvidia on motherboard)

the symptoms make me think the GPU is failing, try with the onboard GPU and let me know, it could be something else but this is the first step in diagnosing.