Okay, so I've been searching around and cannot find anyone else with a similar problem. Basically, sometimes when going into or out of something that is fullscreen, it will just freeze on a black screen. Mouse cursor isn't visible, no keyboard shortcuts work, but Skype still works perfectly fine when this happens. The only thing to do is hold the power button on my laptop, to do a hard restart. This sometimes does seem to coincide with Windows 10 installing updates, but not always. Sometimes it happens with the first fullscreen program I start since turning on my laptop, and sometimes it could be, say, the fifth time I Alt+Tab out of it. I have an Acer Aspire V5 571, running Windows 10 (obviously), and had upgraded from 8.1. I have only had this problem in W10, and it does not occur every time. If you require any extra information to help solve this problem, please ask.