Help me /g/, I figure this is the most appropriate board for this kind of thing, but if not please redirect me.

The problem is that my computer starts up and displays an acer brand icon, then shows some text, and then maybe 5 seconds later "shuts off" and restarts and repeats, which goes on infinitely.

For context this thing is at least 6, if not 7 years old, and has been treated pretty poorly imo. So yesterday my league of legends client wasn't working, so I basically deleted the client and tried to redownload it over night, now typically if I leave my computer idle for too long it likes to shut off the screen, and won't turn on unless I restart the computer, so I just let it download for a few hours over night, and restarted my computer, but then it started to do the issue listed, so I shut it off hoping it would be fine tomorrow, and now it is today and I basically tried downloading a regular version of Windows, but when selected in the boot menu, all I saw was a line to input shit, so idk if I need to know some specific commands or if I'm doing something wrong, or if my comp is RIP, etc.

I'll attach a picture of the end result as well, and sorry if this is poorly worded or if( I sound retarded, I'm just not very tech savvy