Resolve BSOD errors (bad pool header, kernel security check failure, etc)
Windows is a stable OS these days; if you started suddenly to encounter the famous Blue Screen of Death, it is almost certain that one or more of the applications you installed or updated recently causes problems. Even non-faulty applications may prove incompatible with each other, e.g. you’d better not use more than one real-time antivirus scanners. I tried Malwarebytes Antimalware real-time scanner along with AVG, and I suffered several crashes a day!
You may remember what and when you changed and perform a system restore before the day that caused your trouble, but usually you cannot be sure. Fortunately enough there is this light but efficient application called Blue Screen View, that will let you read easily the log files of the BSOD, to learn the problem, research about it online and fix it. (I assume that you have already checked for malware and your system is free from viruses.)
For each crash BlueScreenView displays the minidump filename, the date/time of the crash, the basic crash information of the blue screen (Bug Check Code and 4 parameters), and the details of the driver or module that possibly caused the crash (filename, product name, file description, and file version). BlueScreenView lets you easily locate suspect drivers.
After you locate the problematic application, try to see if an update helps, if not, uninstall it and install it again. Even if this won’t help, perhaps you need to just uninstall and stop using it, until a newer version is released and is proved harmless. Check also this post on what I did when suddenly my PC started to crash regularly.