Hello and welcome to the forum.

Thanks for sending along your bsod report, I will forward this to one of the forum experts and they will get back to you shortly.

Welcome
You have given us about a half a dozen dump reports, with 3 different bug codes.
3B, A and D1

3B
Usual causes: System service, Device driver, graphics driver, ?memory
A
Usual causes: Kernel mode driver, System Service, BIOS, Windows, Virus scanner, Backup tool, compatibility
D1
Usual causes: Device driver

Code:

Microsoft (R) Windows Debugger Version 6.11.0001.404 AMD64
Copyright (c) Microsoft Corporation. All rights reserved.
 
Loading Dump File [C:\Users\richc46\AppData\Local\Temp\Temp2_Windows_NT6_BSOD_jcgriff2 (2).zip\Windows_NT6_BSOD_jcgriff2\Mini060611-01.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 Server 2008/Windows Vista Kernel Version 6002 (Service Pack 2) MP (8 procs) Free x64
Product: WinNt, suite: TerminalServer SingleUserTS Personal
Built by: 6002.18327.amd64fre.vistasp2_gdr.101014-0432
Machine Name:
Kernel base = 0xfffff800`0224a000 PsLoadedModuleList = 0xfffff800`0240edd0
Debug session time: Sun Jun  5 11:52:44.177 2011 (GMT-4)
System Uptime: 0 days 8:51:09.726
Loading Kernel Symbols
...............................................................
................................................................
............................
Loading User Symbols
Loading unloaded module list
...........
*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************
Use !analyze -v to get detailed debugging information.
BugCheck 3B, {c0000005, fffffa60013a7515, fffffa600d4b1e70, 0}
Probably caused by : dxgkrnl.sys ( dxgkrnl!VIDMM_LINEAR_POOL::Free+79 )
Followup: MachineOwner
---------
6: kd> !analyze -v
*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************
SYSTEM_SERVICE_EXCEPTION (3b)
An exception happened while executing a system service routine.
Arguments:
Arg1: 00000000c0000005, Exception code that caused the bugcheck
Arg2: fffffa60013a7515, Address of the exception record for the exception that caused the bugcheck
Arg3: fffffa600d4b1e70, Address of the context record for the exception that caused the bugcheck
Arg4: 0000000000000000, zero.
Debugging Details:
------------------
 
EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%08lx referenced memory at 0x%08lx. The memory could not be %s.
FAULTING_IP: 
dxgkrnl!VIDMM_LINEAR_POOL::Free+79
fffffa60`013a7515 488908          mov     qword ptr [rax],rcx
CONTEXT:  fffffa600d4b1e70 -- (.cxr 0xfffffa600d4b1e70)
rax=0000000000000000 rbx=fffff8800de9df68 rcx=0000000000000000
rdx=fffff8800de9df48 rsi=0000000000000000 rdi=0000000000000000
rip=fffffa60013a7515 rsp=fffffa600d4b26d0 rbp=fffff8800de9df48
 r8=fffffa600d4b2718  r9=fffffa600d4b2720 r10=ffffffffc00000f0
r11=0000000000000001 r12=0000000000000000 r13=0000000000000000
r14=0000000000000000 r15=fffff8800dd59040
iopl=0         nv up ei pl nz na pe nc
cs=0010  ss=0018  ds=002b  es=002b  fs=0053  gs=002b             efl=00010202
dxgkrnl!VIDMM_LINEAR_POOL::Free+0x79:
fffffa60`013a7515 488908          mov     qword ptr [rax],rcx ds:002b:00000000`00000000=????????????????
Resetting default scope
CUSTOMER_CRASH_COUNT:  1
DEFAULT_BUCKET_ID:  VISTA_DRIVER_FAULT
BUGCHECK_STR:  0x3B
PROCESS_NAME:  SC2.exe
CURRENT_IRQL:  0
LAST_CONTROL_TRANSFER:  from fffffa60013a559d to fffffa60013a7515
STACK_TEXT:  
fffffa60`0d4b26d0 fffffa60`013a559d : fffff880`122a4a98 00000000`00000000 00000000`00000000 fffff880`0de9de40 : dxgkrnl!VIDMM_LINEAR_POOL::Free+0x79
fffffa60`0d4b2710 fffffa60`013a550e : 00000000`00000000 fffffa80`0ccd8560 fffffa80`0ab19940 fffffa60`0d4b2768 : dxgkrnl!VIDMM_PROCESS_HEAP::FreeSmallAllocation+0x79
fffffa60`0d4b2750 fffffa60`01391fb4 : 00000000`00000000 fffff880`11180010 00000000`00000001 fffffa60`01390f90 : dxgkrnl!VIDMM_PROCESS_HEAP::Free+0x12e
fffffa60`0d4b2790 fffffa60`0138d830 : fffffa80`08ce0580 00000000`00000000 fffff880`0de9de40 fffff880`0de9de40 : dxgkrnl!VIDMM_GLOBAL::CloseLocalAllocation+0x11c
fffffa60`0d4b2820 fffffa60`0138d6a4 : 00000000`00000000 fffffa60`00000000 00000000`00000001 00000000`00000000 : dxgkrnl!VIDMM_GLOBAL::CloseOneAllocation+0x150
fffffa60`0d4b28f0 fffffa60`01310331 : 00000000`00000000 00000000`00000000 00000000`00000000 fffff880`0820c000 : dxgkrnl!VIDMM_GLOBAL::CloseAllocation+0x44
fffffa60`0d4b2920 fffffa60`0131420f : 00000000`00000000 fffff880`08fdc340 00000000`00000000 fffffa60`0d4b2ca0 : dxgkrnl!DXGDEVICE::DestroyAllocations+0x41d
fffffa60`0d4b2a10 fffffa60`0131663d : fffff880`0820c000 fffffa60`0d4b2b30 fffff880`0820c001 fffff800`02214101 : dxgkrnl!DXGDEVICE::DestroyAllocation+0x3e3
fffffa60`0d4b2ab0 fffff960`00174fc2 : 00000000`08bff120 fffffa80`095bb060 00000000`ffd0a000 00000000`00000020 : dxgkrnl!DxgkDestroyAllocation+0x8dd
fffffa60`0d4b2bf0 fffff800`022a3f33 : 00000000`666aa0b8 fffffa60`0d4b2ca0 00000000`662358a8 00000000`69965870 : win32k!NtGdiDdDDIDestroyAllocation+0x12
fffffa60`0d4b2c20 00000000`7470b6aa : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KiSystemServiceCopyEnd+0x13
00000000`08bfe7f8 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : 0x7470b6aa
 
FOLLOWUP_IP: 
dxgkrnl!VIDMM_LINEAR_POOL::Free+79
fffffa60`013a7515 488908          mov     qword ptr [rax],rcx
SYMBOL_STACK_INDEX:  0
SYMBOL_NAME:  dxgkrnl!VIDMM_LINEAR_POOL::Free+79
FOLLOWUP_NAME:  MachineOwner
MODULE_NAME: dxgkrnl
IMAGE_NAME:  dxgkrnl.sys
DEBUG_FLR_IMAGE_TIMESTAMP:  4d384226
STACK_COMMAND:  .cxr 0xfffffa600d4b1e70 ; kb
FAILURE_BUCKET_ID:  X64_0x3B_dxgkrnl!VIDMM_LINEAR_POOL::Free+79
BUCKET_ID:  X64_0x3B_dxgkrnl!VIDMM_LINEAR_POOL::Free+79
Followup: MachineOwner
---------

Based upon this and other information that you have supplied it is my contention that the cause is a driver, specifically your graphics driver. Update the driver.

SFC /scannow
System Files - SFC Command

Scan with your Anti Virus

There are other possiblites, but less likely. If you get additional BSODs, after following the instructions given,. please post..

Your very welcome. Games can be very big resource users, too much for the graphics card/driver.