Some folks are finding that the latest Patch Tuesday updates resulted in bluescreens.
Info is all over the web but the source of the news and the fix are all found in this Microsoft forum thread:
Blue Screen (Stop 0x50) after applying update KB2982791 to Windows 7 Home Premium 64 bit
The fix is on page 5 of that thread.
Microsoft’s official response, fixes, and recommendation to uninstall up to 4 updates is here:
MS14-045: Description of the security update for kernel-mode drivers: August 12, 2014
Botched Windows Update