In the last month i had occasionally a BSOD whenever the pc was inactive(OS is Windows 10).
I decided i was going to change the HDD in a few months(as an analisys confermed it had some errors because of age).
The situation changed 3 days ago: in the morning i started the pc and (before booting) it automatically started to diagnose and repair the system(don't know why).
After that it restarted and the nightmare began:now the pc continues to restart every ten seconds while showing on screen the BIOS (without text).
Here are the parts of the PC(apart from SSD and HDD)
PSU:Corsair RM 750W
CPU:Intel i5 3330
RAM:8G 2Rx8 DDR3 1600 U
MOBO:Gigabyte GA-B75-D3V rev 1.2
After some researches online i found out that the pc doesn't POST,i tried many things,included the ones i ffound in this list
This are the results:
1)The manual doesn't say anything of importance
2)All the cables are correcly connected
3)I am doing breadbording on a non conductive surface
4,5)Checked,the results are the same if i use the integrated graphics or the old 950 or the 1070
6)I can't access the BIOS and i only have one stick of RAM.I tried all the 4 slots
7 to 10)OK
12 to 14)OK
15)Breadbording so ok
16 to 21)OK
22)Tried integrated graphics,behaviour doesn't change
I cheked the mobo carefully,no signs of damage appear.
With only CPU installed,i hear a series of short beeps,with RAM also installed,no beeps are heard(remember that the mobo has integrated graphics).
POST beep is head only one time out of 20,even in this case the behaviour is the same(no boot).
I replaced GPU and PSU with the previous ones(changed them just to upgrade some months ago) but behaviour is still the same.
Here is a video of the behaviour:the CPU fan can't start in the first seconds and after 10 seconds the system automatically shuts down and restarts creating a loop.
I also checked the CPU state and it appears undamaged(photos here)
My conclusions: PSU,GPU and RAM are surely good.With a probability of 90% the problem is the mobo,the remaining 10% is on the CPU.
Please tell me what is the problem or what i can do to discover it myself.
EDIT:Even without RAM inserted,the system automatically shuts down as usual.