Windows has recovered from an unexpected shutdown

Recently every time that I boot my system I get the above message. The detail reports a blue screen crash even though none is seen:

Problem signature:
Problem Event Name: BlueScreen
OS Version: 6.1.7601.2.1.0.768.3
Locale ID: 2057

Additional information about the problem:
BCCode: 4a
BCP1: 0000000077A4132A
BCP2: 0000000000000002
BCP3: 0000000000000000
BCP4: FFFFF8800C901CA0
OS Version: 6_1_7601
Service Pack: 1_0
Product: 768_1

Files that help describe the problem:
C:\Windows\Minidump\022414-29842-01.dmp
C:\Users\beacon\AppData\Local\Temp\WER-37237-0.sysdata.xml

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C:\Windows\system32\en-US\erofflps.txt

Blue Screen View seems to link it to ntoskrnl.exe

I'm running Bitdefender and Look n Stop firewall. No other security software.

I had to make amendments to my registry recently to allow a WD TV Live box to function correctly - it involved changing the keys related to anonymous user login for windows file sharing, and I have also added a key that adds "run as administrator" to the right click context menu. The problem doesn't seem to be related to those changes, but when I tried to reimport the old registry keys to eliminate that as a possible cause I got an error and the import failed because the registry keys were in use. Even trying to import the backup in safe mode lead to the same error.

I've run check disk and system file verification and there don't seem to be any issues reported. I've updated all my drivers and the problem has persisted. My HDD are all reported as healthy with CrystalDiskInfo and I haven't found any RAM errors with MemTest86

Any help much appreciated, I was wondering about a repair upgrade of Windows to resolve it, but if I can avoid that of course I would like to.

My system details are:
Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: AMD Phenom(tm) II X4 B55 Processor, AMD64 Family 16 Model 4 Stepping 3
Processor Count: 4
RAM: 16382 Mb
Graphics Card: AMD Radeon HD 5700 Series, 1024 Mb
Hard Drives: C: Total - 122103 MB, Free - 27733 MB; D: Total - 439999 MB, Free - 112452 MB; F: Total - 953765 MB, Free - 259648 MB; G: Total - 953866 MB, Free - 386413 MB; K: Total - 305242 MB, Free - 17699 MB; L: Total - 476937 MB, Free - 178 MB; P: Total - 1907726 MB, Free - 100289 MB; R: Total - 2421456 MB, Free - 281740 MB;
Motherboard: ASUSTeK Computer INC., M4A89GTD-PRO
Antivirus: Bitdefender Antivirus, Updated and Enabled

Attached Files

Blue Screen View crash.txt (2.1 KB)