If you normally allow your Windows computer to automatically update itself, then the patch from 12th August may be causing you problems. Namely, the dreaded BSOD, Blue Screen of Death, or as Microsoft more euphemistically but less sensationally refers to it it a crash with a 0×50 Stop error message (bugcheck).
There are various bits of last week’s Patch Tuesday that are causing problems. MS knows about them and has pulled the updates until they’re fixed and recommends that users uninstall specific updates:
2982791 MS14-045: Security update for kernel-mode drivers
2970228 Update to support the new currency symbol for the Russian ruble
2975719 Update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2
2975331 Update rollup for Windows RT, Windows 8, and Windows Server 2012
More details can be found here along with instructions, if you don’t know how to revert/uninstall Windows updates.