Question PC Shuts off randomly

[XGamer_BiH]

Hello folks,
so this issue has been giving me headaches lately. PC shuts off randomly, mostly during gaming, but today I experienced a shut down during idling at the desktop.

Earlier, I had the weird issue that my mouse would simply disconnect (only during gaming), first outcome: if not touched or moved, it may reconnect and keep on going, second outcome: it will switch on and off like 10 times in 10 seconds, and eventually shut down the pc, and third outcome: if I unplug the mouse including other USB devices, everything keeps on going without trouble.

Now, lately, my mouse doesn't even disconnect, the PC just shuts down, I NEVER got any BSODs, or anything informing about a unexpected system crash - PC boots fine without trouble or any errors or messages.

Also, my keyboard also used to disconnect the same way the mouse did, causing same issues. Some may say that hardware is the issue here - replace the mouse or keyboard, but, if it's the hardware, why don't such issues happen outside of gaming, since it mostly happens during gaming.

Sometimes, it also refuses to start after the shut down, not any errors or such, but I start, it runs for like 5 seconds and shuts down, sometimes 10 seconds, sometimes 12 seconds etc. so it's NEVER the same timing, also the shut downs are random, so no given timer or anything like that.

Temps are competely normal, both GPU and CPU don't go above 75C, also the game doesn't matter, it just matters that the PC is under a load.
I'm starting to think it's the PSU, but sometimes it shuts down under 10 minutes, sometimes after a hour, sometimes never during multiple hours of gaming.

Also I did do a general cleanup from dust inside the case, including the PSU, but the issue remains.
Also did some general software work, like checking for malware and viruses - everything is clean.
Also checked the 12V and 5V rails during gaming with a multimeter, all the voltages are in a safe region, they don't drop during gaming.

specs:
Asus H61M-C
i5 3470 stock
8GB DDR3 RAM
256GB Samsung SSD
WD 1TB HDD
LC Power LC600H-12

I know the PSU is kinda garbge, but it has been fine for the 5 years I own it already.
Thanks in advance!

 

[rgd1101]

test with a better psu

 

[DSzymborski]

Yup, I don't think I'd let an LC Power in my house, let alone inside my computer.

 

[XGamer_BiH]

Alright, thanks. I'll try to get a new one!

 

[DSzymborski]

I unmarked my answer as best answer. Getting a new power supply that's dependable and safe is the first step of diagnosing, but it may not be the last.

 

[XGamer_BiH]

That's the only thing I can really do, I tested anything there was to do, since it's a cheapo PSU, it gotta be it.
It just started happening, without any prior mods to the case or wiring or anything like that, it just started doing so. I'll try to get a different PSU, and also check my RAM sticks.