Problem with startup

Hey had this problem for a little while, PC decides it doesnt want to startup either by not passing through the "starting windows" screen or after typing in my password, also somtimes gets the same problem shutting down. so i'm forced to plug pull to restart into safe mode.

Currently in Safe mode and i got this info from the latest 'plug pull' i had.

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: 9f
BCP1: 0000000000000003
BCP2: FFFFFA800F1E7870
BCP3: FFFFF80000B9C3D8
BCP4: FFFFFA8010CDB240
OS Version: 6_1_7601
Service Pack: 1_0
Product: 768_1

Files that help describe the problem:
C:\Windows\Minidump\040512-16567-01.dmp
C:\Users\Dan\AppData\Local\Temp\WER-29546-0.sysdata.xml

I archived the minidump folders, can anyone help?
Thanks.

Go here and do the memory and hard drive tests:
http://www.techspot.com/vb/topic51365.html

You can set a disk check from the Safe Mode and Memtest86 is run from a bootable CD before Windows starts