APOLOGIES FOR THE BIG POSTING BUT I THINK WHAT I HAVE SAID IS IMPORTANT..... keep me informed on the outcome
even if this guy is a friend you need to talk to him , the least he should do is come round and see what your problem is , lights on anything mean nothing for a few years now a pc mobo supplies power to usb even when it is turned off , basically a turned off pc acts like a battery charger that's why you see lights on something that's not working., when you plug anything into a pc you should hear a door bell type noise and a little box pop up saying new device found , it may even say what it is.
Their are all sorts of things you can enable/disable in something called bios settings.
you really need to ask him what he did to the pc before he handed it over to you. As well as clearing out personal items he could have done something he has not told you.
ALARM BELLS RINGING ……….. why don't you have an operating system on the pc ???? that means he MUST have removed it and I cant think of any reason why he would do that, I have a custom built pc and I also have the windows 10 disc of the os. Did he give you the os disc.
If he is trying to rip you of by using the windows disc on another pc he will come unstuck because when he HAS to register the op sys on another pc Microsoft will detect it has already been used on something else and block his install.
You say he is a friend but If my suspicions are right there is something he is not telling you.