Startup screen shifting to top-right corner + USB failing to be read??

Hello guys,

Okay, so I've basically got two questions, but I'm going to put them both in one thread.

First one is about the startup screen. I have El Captain, and I think it was ever since I updated, that it has been doing this. Just when startup is just about finished loading, the screen (the apple logo and the loading bar) shifts (or kinda flashes? Like, you can't see the transition or anything) to the top-right corner. Also, when it's done, the cursor always shows up in the top-right corner, right at the end there. Is this normal? I don't really like the look of it, it kinda seems a little suspicious to me :3

The other question, is that my Mac won't recognise my USB. I've tried putting it in both ports, and I've put in another USB, and that one works. It was working fine yesterday. The USB has a little light indicator to say when it's connected, and when I put it in, it flashes, but it doesn't stay lit, whereas usually it does. I tried resetting(?) the PRAM, the light went on, but my Mac didn't register it. I also reset the SMC, but it nothing.

Another thing I tried, was Safe Reboot. That caused my USB to stop lighting up, and going back to how it was before. While in Safe Mode, that startup screen thing didn't happen, but when I reboot my computer normally, it did it again.

So, in conclusion, does anyone have a resolution? Does anyone know what's wrong (if there is anything wrong at all) and how I can fix it (the USB one at least, I need to use it real soon for a school assignment thing!)

Ta xx

~ Gigi