Weird blue screens of death - help!

Here is what whocrashed came up with:

Crash Dump Analysis
--------------------------------------------------------------------------------

Crash dump directory: C:\Windows\Minidump

Crash dumps are enabled on your computer.

On Fri 11/04/2014 16:49:41 GMT your computer crashed
crash dump file: C:\Windows\Minidump\041114-6224-01.dmp
This was probably caused by the following module: dxgmms1.sys (dxgmms1+0x28559)
Bugcheck code: 0x3B (0xC0000005, 0xFFFFF880049D3559, 0xFFFFF8800CD31730, 0x0)
Error: SYSTEM_SERVICE_EXCEPTION
file path: C:\Windows\system32\drivers\dxgmms1.sys
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: DirectX Graphics MMS
Bug check description: This indicates that an exception happened while executing a routine that transitions from non-privileged code to privileged code.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in a standard Microsoft module. Your system configuration may be incorrect. Possibly this problem is caused by another driver on your system that cannot be identified at this time.



On Thu 10/04/2014 21:16:21 GMT your computer crashed
crash dump file: C:\Windows\Minidump\041014-7441-01.dmp
This was probably caused by the following module: watchdog.sys (watchdog+0x122F)
Bugcheck code: 0x10E (0x1F, 0xFFFFF8A01725CE50, 0x0, 0x5A6078)
Error: VIDEO_MEMORY_MANAGEMENT_INTERNAL
file path: C:\Windows\system32\drivers\watchdog.sys
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: Watchdog Driver
Bug check description: This indicates that the video memory manager has encountered a condition that it is unable to recover from.
The crash took place in a standard Microsoft module. Your system configuration may be incorrect. Possibly this problem is caused by another driver on your system that cannot be identified at this time.



On Fri 04/04/2014 02:44:19 GMT your computer crashed
crash dump file: C:\Windows\Minidump\040414-7316-01.dmp
This was probably caused by the following module: ntoskrnl.exe (nt+0x75BC0)
Bugcheck code: 0x50 (0xFFFFFA8018E11E00, 0x0, 0xFFFFF800034D4B46, 0x2)
Error: PAGE_FAULT_IN_NONPAGED_AREA
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This indicates that invalid system memory has been referenced.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.



On Sat 29/03/2014 19:26:15 GMT your computer crashed
crash dump file: C:\Windows\Minidump\032914-6973-01.dmp
This was probably caused by the following module: ntoskrnl.exe (nt+0x75BC0)
Bugcheck code: 0x19 (0x20, 0xFFFFFA80117BACB0, 0xFFFFFA80117BB530, 0x4880009)
Error: BAD_POOL_HEADER
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This indicates that a pool header is corrupt.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem. This might be a case of memory corruption. More often memory corruption happens because of software errors in buggy drivers, not because of faulty RAM modules.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.



On Sat 29/03/2014 16:57:40 GMT your computer crashed
crash dump file: C:\Windows\Minidump\032914-7550-01.dmp
This was probably caused by the following module: ntoskrnl.exe (nt+0x75B90)
Bugcheck code: 0x1E (0x0, 0x0, 0x0, 0x0)
Error: KMODE_EXCEPTION_NOT_HANDLED
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This indicates that a kernel-mode program generated an exception which the error handler did not catch.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.



On Tue 18/03/2014 22:26:12 GMT your computer crashed
crash dump file: C:\Windows\Minidump\031814-68624-01.dmp
This was probably caused by the following module: hal.dll (hal+0x12A3B)
Bugcheck code: 0x124 (0x0, 0xFFFFFA800C702028, 0xB67B2000, 0xA000145)
Error: WHEA_UNCORRECTABLE_ERROR
file path: C:\Windows\system32\hal.dll
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: Hardware Abstraction Layer DLL
Bug check description: This bug check indicates that a fatal hardware error has occurred. This bug check uses the error data that is provided by the Windows Hardware Error Architecture (WHEA).
This is likely to be caused by a hardware problem problem. This problem might be caused by a thermal issue.
The crash took place in a standard Microsoft module. Your system configuration may be incorrect. Possibly this problem is caused by another driver on your system that cannot be identified at this time.



On Wed 19/02/2014 21:49:31 GMT your computer crashed
crash dump file: C:\Windows\Minidump\021914-14086-01.dmp
This was probably caused by the following module: hal.dll (hal+0x12A3B)
Bugcheck code: 0x124 (0x0, 0xFFFFFA800D518028, 0xB6004000, 0xE9000175)
Error: WHEA_UNCORRECTABLE_ERROR
file path: C:\Windows\system32\hal.dll
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: Hardware Abstraction Layer DLL
Bug check description: This bug check indicates that a fatal hardware error has occurred. This bug check uses the error data that is provided by the Windows Hardware Error Architecture (WHEA).
This is likely to be caused by a hardware problem problem. This problem might be caused by a thermal issue.
The crash took place in a standard Microsoft module. Your system configuration may be incorrect. Possibly this problem is caused by another driver on your system that cannot be identified at this time.



On Wed 15/01/2014 21:27:32 GMT your computer crashed
crash dump file: C:\Windows\Minidump\011514-10732-01.dmp
This was probably caused by the following module: l6ux164.sys (Unloaded_L6UX164.sys+0x71078)
Bugcheck code: 0xCE (0xFFFFF88008CFD078, 0x8, 0xFFFFF88008CFD078, 0x2)
Error: DRIVER_UNLOADED_WITHOUT_CANCELLING_PENDING_OPERATIONS
file path: C:\Windows\system32\drivers\l6ux164.sys
product: GuitarPort
company: Line 6
description: GuitarPort WDM Audio Device Driver
Bug check description: This indicates that a driver failed to cancel pending operations before unloading.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
A third party driver was identified as the probable root cause of this system error. It is suggested you look for an update for the following driver: l6ux164.sys (GuitarPort WDM Audio Device Driver, Line 6).
Google query: Line 6 DRIVER_UNLOADED_WITHOUT_CANCELLING_PENDING_OPERATIONS



On Fri 08/11/2013 23:29:49 GMT your computer crashed
crash dump file: C:\Windows\Minidump\110813-9547-01.dmp
This was probably caused by the following module: l6ux164.sys (Unloaded_L6UX164.sys+0x71078)
Bugcheck code: 0xCE (0xFFFFF88009278078, 0x8, 0xFFFFF88009278078, 0x2)
Error: DRIVER_UNLOADED_WITHOUT_CANCELLING_PENDING_OPERATIONS
file path: C:\Windows\system32\drivers\l6ux164.sys
product: GuitarPort
company: Line 6
description: GuitarPort WDM Audio Device Driver
Bug check description: This indicates that a driver failed to cancel pending operations before unloading.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
A third party driver was identified as the probable root cause of this system error. It is suggested you look for an update for the following driver: l6ux164.sys (GuitarPort WDM Audio Device Driver, Line 6).
Google query: Line 6 DRIVER_UNLOADED_WITHOUT_CANCELLING_PENDING_OPERATIONS



On Sun 03/11/2013 19:46:40 GMT your computer crashed
crash dump file: C:\Windows\Minidump\110313-68172-01.dmp
This was probably caused by the following module: hal.dll (hal+0x12A3B)
Bugcheck code: 0x124 (0x0, 0xFFFFFA800CA04028, 0xB614C000, 0x135)
Error: WHEA_UNCORRECTABLE_ERROR
file path: C:\Windows\system32\hal.dll
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: Hardware Abstraction Layer DLL
Bug check description: This bug check indicates that a fatal hardware error has occurred. This bug check uses the error data that is provided by the Windows Hardware Error Architecture (WHEA).
This is likely to be caused by a hardware problem problem. This problem might be caused by a thermal issue.
The crash took place in a standard Microsoft module. Your system configuration may be incorrect. Possibly this problem is caused by another driver on your system that cannot be identified at this time.