Hello! I really hope someone can give me an answer, like 3/4 years ago a friend bought a prebuilt system:
CPU: i5 4440
MOBO: ECS H81
RAM: 4 GB Kingston value
HDD: 500 GB WD Blue
PSU: generic 450w
CASE: generic
(I want to make an appointment, all the parts we tested from other builds were correctly working previously in it's respect systems).
So time after he decided to upgrade it, so he bought a GTX 960+EVGA 500w power supply, BUT something weird happened, the computer randomly restarted no matter what do you do, it could be: less than 5 secs you log into windows, whatching YouTube, playing games(not all, some games that demand little GPU power made it restart), with ms office, watching movies, i think even in idle(it had no consistency on usage time, it could be 5 mins or 4 hours).
Tried reinstalling windows (with windows 8.1 and windows 10).
We thought it might be the PSU, so he bought an Antec VP500P, just to see that the same day it restarted. I gave him my Antec VP550F that was fully working in my system at the time(i5 3330+GTX 760+h61 mobo) but AGAIN it restarted.
It may be the the motherboard, so we changed it for a MSI H81M-P33, tried factory settings, disabling power efficiency settings, etc.
Then trying luck with a Cougar MX idk well the model case, but didn't work.
Tried with his brother HDD.
Lastly changed the RAM for another 4GB Kingston value he had from a previous system, also bought a 8GB single stick from another friend system.
A friend recommended changing the HDMI cable, so he bought an expensive asf cable but the pc STILL restarted.
Also we tried in my house with my GTX 760 + my PSU in his (literally) new PC (new msi mobo + new RAM + new HDMI), but no matter what it restarted!!
That PC made me truly angry, the only way that thing didn't restart was without a dedicated GPU.
In total we changed:
CPU: i5 4440
MOBO: ECS H81 --------------------------> H81M-P33
GPU: not included in prebuilt ----> GTX 960 ---> GTX 760(mine)
RAM: 4 GB Kingston value --------> another 4GB Kingdom value from previous system --> 8GB Novatech from a friend system
HDD: 500 GB WD Blue ---------------> his brother HDD
PSU: generic 450w -------------------> EVGA 500W ----> Antec VP500P ---> Antec VP550F(mine)
CASE: generic ----------------------------> Cougar case