Windows Machine Won't Boot With USB Port Active

I've been having an issue with my Acer S7-391. I bought the Windows 8 machine in December, and the majority of the time when I start it up in the morning, it doesn't boot properly - it hangs on a black screen for ages. I then have to hit the off button and boot it back up again and, sometimes, it boots after having to go through a system repair. Also, sometimes it does boot properly from the get-go without having to jump through hoops - not often though.

Originally I thought it was an issue with me having upgraded to Windows 8.1 shortly after buying the laptop, but having rolled the machine back to Windows 8, the issue prevailed. Through trial and error, though, I've figured out when it does and when it doesn't boot properly (yeah, I'm slow). Basically, it never boots properly when I have a USB mouse/keyboard plugged in. I take them out, boot the machine, and can plug them in again almost immediately and everything works fine. But NEVER does it boot with these devices plugged in from the start.

Here's a photo of it anyway (below).

Any solution here - other than unplugging my USB peripherals on boot - t'