Reason for crashes?

[mephistobse]

Since i bougth my desktop pc im having the same problem wich is random crashes, not all the time and not in all the games i play.
The symptons are as follows:
Im playing normaly, then the screen goes black in the following 2 to 3 seconds the sonds dies as well, and to use the pc again i have to hard reset.
When i start the computer again there is no crash log in the windows event log it just says I shut down the pc incorrectly.
The games I can replicate the problems are: League of legends (the first game i play and then it doesnt occur again until i shut down the pc completly, except today that it crashes twice in a row), Grim dawn (only once) and divinity original sin(in the rain sector, i play like 5 to 7 minutes there and it crashes withouth fail, so I think it maybe the gpu)

My pc specs are as follows.
Sentey 500v psu
Intel i5-7400 proccesor
Gygabyte ga-m110h-m motherboard
8Gb ddr4 ram kingston
Geforce gt 430 gpu (this one i didnt buy, this was gifted, so its used)
A kelyx monitor (old giant one)
Tp-link usb wireless adapter.
windows 10 professional.
only got the fabric coolers.

 

[mephistobse]

You can close this i found out it was the fan that was stuck so i added some w-40 and renewed the thermal paste, and it was solved.