Random BSOD's: Memory_management, bad pool header etc.

Post the dumps you get after doing the steps in the tutorial.

We'll see what we can do.

Update your DirectX from here.
DirectX Update

Driver Reference Table

Code:

STACK_COMMAND:  kb

FOLLOWUP_IP: 
dxgmms1!VidSchiIsHardwareCompletedDependingCommandForFlip+18
fffff880`0437b4d4 448b9084000000  mov     r10d,dword ptr [rax+84h]

SYMBOL_STACK_INDEX:  3

SYMBOL_NAME:  dxgmms1!VidSchiIsHardwareCompletedDependingCommandForFlip+18

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: dxgmms1

IMAGE_NAME:  dxgmms1.sys

DEBUG_FLR_IMAGE_TIMESTAMP:  4ce799c1

FAILURE_BUCKET_ID:  X64_0xD1_dxgmms1!VidSchiIsHardwareCompletedDependingCommandForFlip+18

BUCKET_ID:  X64_0xD1_dxgmms1!VidSchiIsHardwareCompletedDependingCommandForFlip+18

Followup: MachineOwner
---------

3: kd> lmvm dxgmms1
start             end                 module name
fffff880`0436d000 fffff880`043b3000   dxgmms1    (pdb symbols)          c:\symbols\dxgmms1.pdb\0901C357E9E846EE8C2FBCC8107163201\dxgmms1.pdb
    Loaded symbol image file: dxgmms1.sys
    Mapped memory image file: c:\symbols\dxgmms1.sys\4CE799C146000\dxgmms1.sys
    Image path: \SystemRoot\System32\drivers\dxgmms1.sys
    Image name: dxgmms1.sys
    Timestamp:        Sat Nov 20 15:49:53 2010 (4CE799C1)
    CheckSum:         00047A89
    ImageSize:        00046000
    File version:     6.1.7601.17514
    Product version:  6.1.7601.17514
    File flags:       0 (Mask 3F)
    File OS:          40004 NT Win32
    File type:        3.7 Driver
    File date:        00000000.00000000
    Translations:     0409.04b0
    CompanyName:      Microsoft Corporation
    ProductName:      Microsoft® Windows® Operating System
    InternalName:     dxgmms1.sys
    OriginalFilename: dxgmms1.sys
    ProductVersion:   6.1.7601.17514
    FileVersion:      6.1.7601.17514 (win7sp1_rtm.101119-1850)
    FileDescription:  DirectX Graphics MMS
    LegalCopyright:   © Microsoft Corporation. All rights reserved.

Get the latest drivers for your graphics card as well.

Post back if you get more dumps.

Check this link and tell me if that's your card.
ASUS - Graphics Cards- ASUS ENGTX550 Ti DC/DI/1GD5

If yes, go to the download tab and download the driver (64 bit in your case)

Good luck

Post dumps if you get them.