Question latency / stuttering


Oct 3, 2018
First of all English is not my first language...but I will try my best to explain my big problem.
So, about 3 months ago my pc randomly goes black screen i was playing gta iv, ok i thought something crashed and restarted my pc and everything was working fine, then after one or two weeks same happened but this time i was on youtube watching stuff and I suspected either gpu or psu.
After some time there was no black screen, i was playing csgo and pc started stuttering (audio and video) (i had win 8.1 back then) i exited all unnecessary programs, deleted junk files, defragmented my hdd but nothing.
Now I was 100% sure it was gpu (the culprit) but i wasn't doing anything. 2 days later i tried to turn on my pc but no screen, i tried taking out ram and putting it back and nothing. Then i tried my IG gpu and it worked everything was fine. I installed win 10 because i was bored of 8.1 and i put my gpu in oven hahahha. Luckily it worked but i knew it wasn't going to work for long time. But the stutter was doing its job again I had like 250 fps const and it would drop to 80-90 and go back to normal every 2-3 min or so.
I tried to find a fix on google and saw latencymon and i've been trying to fix that problem last 3 weeks..
My gpu died again and i don't want to bake it again I started saving money for another gpu. But the problem now is pc stuttering even with the IG gpu, i've tried a lot of things:
-high performance **** (even i use high performance all the time)
-flashing new BIOS
-downloading drivers from the mobo site
-disabling hpet, speedstep, turbo boost, c states
-disabling drivers in device manager
-reinstalling windows like 20 times
-updating audio drivers, AHCI driver in devmgmt
-checking ram, trying even different psu
-updating intel r network drivers etc etc..

I'm running out of ideas, i really don't know what else to try, only thing i didn't try to swap is hdd but i don't think that is the problem i checked it with various programs and it is 100% health.
I don't have money to buy another pc because i got this one 6-7 months ago, i'm 17yo boy btw still going to school.

PC specs:
i5 2400
lenovo oem mobo
8gb ram ddr3 1333mhz
500gb seagate hdd
500w fsp 80+ bronze psu
and hd 5750 dead gpu haha

i know this is old hardware but for my needs it is good, budget variant. Thanks in advance :)