Pc wont post-boot

Hello,just got a new pc ,last week i switched off psu due to planning on being away and two days ago when i hit the power button it appeared to boot but i noticed that the gpu rgb light was on despite me having it off from day one from its software,keyboard had no power and mouse and monitor too,i tried to shut it down holding power button but the moment i pressed it shut down instantly,this has happened twice now at random occasions and although i have no other issues nor hear any beeps or mobo led light indication im wondering if something serious is going on and what my best course of action should be,also my pc was running fine for 2 weeks and i always switch off psu couple of minutes after it has shut down

Thanks in advance for your time