External HD BSOD

My plug and play external HD was working fine for a while but has recently been giving my problems. Windows doesnt detect it anymore when I plug it in, and when I turn it off I get a BSOD. I downloaded the MS debugger tool but Im kinda confused as to what I should do with the information it gives me.

Here's the minidump


Microsoft (R) Windows Debugger Version 6.8.0004.0 X86
Copyright (c) Microsoft Corporation. All rights reserved.


Loading Dump File [C:\WINDOWS\Minidump\Mini121307-03.dmp]
Mini Kernel Dump File: Only registers and stack trace are available

Symbol search path is: SRV*c:\symbols*http://msdl.microsoft.com/download/symbols
Executable search path is:
Windows XP Kernel Version 2600 (Service Pack 2) MP (2 procs) Free x86 compatible
Product: WinNt, suite: TerminalServer SingleUserTS
Built by: 2600.xpsp_sp2_gdr.070227-2254
Kernel base = 0x804d7000 PsLoadedModuleList = 0x8055c700
Debug session time: Thu Dec 13 11:31:33.171 2007 (GMT-5)
System Uptime: 0 days 0:01:57.890
Loading Kernel Symbols
...............................................................................................................................................
Loading User Symbols
Loading unloaded module list
.................
Unable to load image arpolicy.sys, Win32 error 0n2
*** WARNING: Unable to verify timestamp for arpolicy.sys
*** ERROR: Module load completed but symbols could not be loaded for arpolicy.sys
*******************************************************************************
* *
* Bugcheck Analysis *
* *
*******************************************************************************

Use !analyze -v to get detailed debugging information.

BugCheck 1000007E, {c0000005, 805887b3, bacefbcc, bacef8c8}



Probably caused by : arpolicy.sys ( arpolicy+177d )

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

0: kd> !analyze -v
*******************************************************************************
* *
* Bugcheck Analysis *
* *
*******************************************************************************

SYSTEM_THREAD_EXCEPTION_NOT_HANDLED_M (1000007e)
This is a very common bugcheck. Usually the exception address pinpoints
the driver/function that caused the problem. Always note this address
as well as the link date of the driver/image that contains this address.
Some common problems are exception code 0x80000003. This means a hard
coded breakpoint or assertion was hit, but this system was booted
/NODEBUG. This is not supposed to happen as developers should never have
hardcoded breakpoints in retail code, but ...
If this happens, make sure a debugger gets connected, and the
system is booted /DEBUG. This will let us see why this breakpoint is
happening.
Arguments:
Arg1: c0000005, The exception code that was not handled
Arg2: 805887b3, The address that the exception occurred at
Arg3: bacefbcc, Exception Record Address
Arg4: bacef8c8, Context Record Address

Debugging Details:
------------------




EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".

FAULTING_IP:
nt!IoUnregisterPlugPlayNotification+13
805887b3 8b5f24 mov ebx,dword ptr [edi+24h]

EXCEPTION_RECORD: bacefbcc -- (.exr 0xffffffffbacefbcc)
ExceptionAddress: 805887b3 (nt!IoUnregisterPlugPlayNotification+0x00000013)
ExceptionCode: c0000005 (Access violation)
ExceptionFlags: 00000000
NumberParameters: 2
Parameter[0]: 00000000
Parameter[1]: 00000026
Attempt to read from address 00000026

CONTEXT: bacef8c8 -- (.cxr 0xffffffffbacef8c8)
eax=00000002 ebx=00000000 ecx=0000007d edx=8a0e39f4 esi=806e4940 edi=00000002
eip=805887b3 esp=bacefc94 ebp=bacefca8 iopl=0 nv up ei pl nz na po nc
cs=0008 ss=0010 ds=0023 es=0023 fs=0030 gs=0000 efl=00010202
nt!IoUnregisterPlugPlayNotification+0x13:
805887b3 8b5f24 mov ebx,dword ptr [edi+24h] ds:0023:00000026=????????
Resetting default scope

CUSTOMER_CRASH_COUNT: 3

PROCESS_NAME: System

ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".

READ_ADDRESS: 00000026

BUGCHECK_STR: 0x7E

DEFAULT_BUCKET_ID: NULL_CLASS_PTR_DEREFERENCE

LOCK_ADDRESS: 8055a4e0 -- (!locks 8055a4e0)

Resource @ nt!PiEngineLock (0x8055a4e0) Available

WARNING: SystemResourcesList->Flink chain invalid. Resource may be corrupted, or already deleted.


WARNING: SystemResourcesList->Blink chain invalid. Resource may be corrupted, or already deleted.

1 total locks

PNP_TRIAGE:
Lock address : 0x8055a4e0
Thread Count : 0
Thread address: 0x00000000
Thread wait : 0x0

LAST_CONTROL_TRANSFER: from b9d0a77d to 805887b3

STACK_TEXT:
bacefca8 b9d0a77d 00000002 8055a720 e1ab9200 nt!IoUnregisterPlugPlayNotification+0x13
WARNING: Stack unwind information not available. Following frames may be wrong.
bacefcc4 80588785 bacefd70 8a04ac08 8a63dda8 arpolicy+0x177d
bacefcec 80588e95 b9d0a66a bacefd24 8a04ac08 nt!PiNotifyDriverCallback+0x6f
bacefd50 805995d3 e699a828 e699a84c bacefd70 nt!IopNotifyDeviceClassChange+0xb5
bacefd7c 805379bd 898e2628 00000000 8a63dda8 nt!PiWalkDeviceList+0xe1
bacefdac 805ce84c 898e2628 00000000 00000000 nt!ExpWorkerThread+0xef
bacefddc 8054532e 805378ce 00000001 00000000 nt!PspSystemThreadStartup+0x34
00000000 00000000 00000000 00000000 00000000 nt!KiThreadStartup+0x16


FOLLOWUP_IP:
arpolicy+177d
b9d0a77d ?? ???

SYMBOL_STACK_INDEX: 1

SYMBOL_NAME: arpolicy+177d

FOLLOWUP_NAME: MachineOwner

MODULE_NAME: arpolicy

IMAGE_NAME: arpolicy.sys

DEBUG_FLR_IMAGE_TIMESTAMP: 42efff71

STACK_COMMAND: .cxr 0xffffffffbacef8c8 ; kb

FAILURE_BUCKET_ID: 0x7E_arpolicy+177d

BUCKET_ID: 0x7E_arpolicy+177d

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


All of the minidumps in the minidump folder point to arpolicy.sys