HTC One X - stuck on "Quietly Brilliant"

[AC Question]

Hi!

I recently got a secondhand HTC One X from a a friend of a friend who hadn't started it in more than half a year. After charging it for a couple of hours until the light became green instead of red, I tried to start it up and it hung on "Quietly Brilliant" for ~15 minutes and then just shut off again. It only did this once, afterwards it would only charge, do some vibrating when I tried to turn it on, and have a flashing red light sometimes. I tried some things I found online to get to the Quietly Brilliant screen again and luckily I got that to work. After charging, I held both volume buttons as well as the power button for 2 minutes and it would start the Quietly Brilliant screen like 20 times. Sadly, it didn't get past that screen and I am out of idea's on what to do or google. Hoping someone has an idea!

P.S. I don't know much about Android in terms of rooting or anything, so please explain throhoughly if you don't mind!
P.S.S. It is not a problem at all to reset the phone if that's neccesarry. I never installed Android on a device but if that might fix it, I'm completely open to it!

Thanks for reading