pc shuts off while playing games

my pc keeps shutting off while playing Siege. Sometimes it shuts off while running hot, sometimes the temps are completely fine and it just shuts off my pc while playing. I've updated drivers, applied new thermal paste and checked game files, all are fine. The only thing i can think of is that...

I have 50 mbps on both download and upload speeds. I have checked on speedtest.net and it gives me those speeds, but whenever I try to download something, It downloads like at 350 KB. This happens to almost all websites except Steam. I can download games at full speed from there. I even tested...