Question PC stuck in boot loop,no bios

[Hashem_1]

Hey there.
After years of being deprived of gaming I finally move out and I decide to put together my deconstructed PC.
I bought a new GPU,RAM,an SSD,and a gaming monitor.i put everything in and I had some issues where the PC stays in a reboot loop in which it boots ,no bios/display stays on for a about 2 to 5 seconds and crashes or shutsdown immediately,what I did was I disconnected the GPU and used my previous old one and the PC worked,I thought the new GPU was busted because it fell from knee height once but I didn't give up and I plugged the new GPU back in and it worked idk how or why.
Everything goes well I played apex legends and its fucking awesome,I started packing it with the usual shit I play and use like photoshop,league of legends,blueJ,and other stuff for uni.
After exactly three days I press the "update and shutdown" button and go to sleep,next day I go to uni and come back to switch it on,the same issue happens again so I was like okay it's not software for sure,its hardware because it's the same like last time and the SSD didn't even have windows last time,and because there is no bios so hardware for sure,I do what I did the first time it happened and I switch GPUs,didn't work so I said maybe other shit is going on,i switch between all the parts and try everything.no ram,with ram,no GPU and using integrated GPU,removing the other HDDs I had on,no disks at all,so I thought it's either motherboard,CPU,or PSU.
I am posting here today to ask for the PC community's advice on this matter,honestly I dont know what to do
Please help me out,do I have to buy a new PSU because that's what the guy i asked at a local PC parts store told me I'll have to do and he seemed like a guy who knows his shit,I just dont want to make stupid decisions.


PS.my setup is as follows (dont have any software to detect it so bare with me)
GPU: old is gtx960 new is rx580
CPU:I5-4460(I have another one which I didn't use because I dont have thermal paste it's an i5-2400)
Motherboard:gigabyte GA-H81M-S2PT(same thing here the other motherboard is...idk cant find the model number)
RAM:CORSAIR Vengence ddr3 8gb 1600ghz
PSU:EVGA 500B 500w
Storage:sandisk ultra 3d SSD 256gb and a 1tb Toshiba HDD



Thanks for reading all this I am sorry it's so long.

 

[thatcakedontbake]

Let's try going with the local PC parts store guy's angle.

How long have you used your EVGA 500B for?

 

[Hashem_1]

Let's try going with the local PC parts store guy's angle.

How long have you used your EVGA 500B for?

I bought the PC when 960 was fairly new so maybe 4 years ago? 4 years old I am saying

 

[thatcakedontbake]

I bought the PC when 960 was fairly new so maybe 4 years ago? 4 years old I am saying

Ok. Following this route--you can try to bring your pc to the store and have him check if it actually is a PSU problem by using their own test PSU unit.

On a different angle, when you try to turn on your PC, try to get close to your pc case and listen if there are any beeps. If something's wrong during the bootup, there should be some beeps (combination of longs and shorts). Get the combination, post it here.

 

[Hashem_1]

Ok. Following this route--you can try to bring your pc to the store and have him check if it actually is a PSU problem by using their own test PSU unit.

On a different angle, when you try to turn on your PC, try to get close to your pc case and listen if there are any beeps. If something's wrong during the bootup, there should be some beeps (combination of longs and shorts). Get the combination, post it here.

I've never had beeps in my system I think it's a motherboard thing