Aaagh!
Ruddy Windows 10!
Microsoft normally turn everything in their software 'on' by default. So, for example, trying to type a numbered list the way that
I want to do it in Microsoft Word is an absolute pain because Word comes with automatic numbering and indenting turned on (and thus tries to make my list look as Microsoft's programmers think that it ought to, rather than as I want it to be).
However, with Windows 10, the one thing which really, really needs to be turned 'on' by default (System Restore) is turned 'off' when you first install the operating system! So no restore points are created until you've turned the ruddy thing on (which, for most people, is too late because something's already gone wrong before they find that out!)
http://home.bt.com/tech-gadgets/computing/how-to-fix-windows-10-problems-with-system-restore-11364008291943
As I wrote before though, if the problem's only present when your browser is open, uninstalling it (and then reinstalling it) is likely to fix the problem.