BAD_POOL_HEADER

Stop  0X00000019 (0x00000020, 0x.., 0x..)
The bad pool header error can be caused by:
undervoltage (bad power supply),
a driver conflict (try turning off the USB printer during a backup),
hardware device not working (network card, video card)
bad memory: RAM nodules and perhaps the hibernation or virtual memory files (hiberfil.sys or pagefile.sys) [also NTFS problem (corruption)],
bad sectors on the hard drive
a corrupt registry entry or
a filesystem problem,
a old or bad driver. etc.
First disconnect any external devices connected to the computer except the mouse and keyboard, check what happens.
To simple determination of faulty RAM,  try running with minimum amount of RAM sticks.
-----------------------
This error can have two causes:
   The first one is the Indexing service.
Click Start, then Run and type msconfig. In the Services tab, uncheck Indexing Service. Confirm and restart Windows
   The second one is a file or folder is damaged.
Open Windows Explorer. Then click on each folder and subfolder. If the error occurs again, you know that the file is damaged that you just activated.
Reboot Windows and delete the folder.
Bug Check 0x19: BAD_POOL_HEADER
Source

1.  Check the disk using chkdks /r command.
In NT 6.1 systems: chkdsk /f).

2.  Scan the system file using sfc /scannow command.

3.  Use Memory Diagnostic utility to check memory.

•    Reboot computer, keep pressing F8, choose "Repair Your Computer" when startup menu appear.
•   Click "Next" and type user password  if prompt, click next.
•   Press the Tab key on the keyboard to highlight "Windows Memory Diagnostic" and press the Enter key.

4.  Update all device drivers and install updates. 

5. Check the system files using sfc /scannow command (you need the last installation DVD)