Computer keeps randomly rebooting.

Alright, where to begin? A year or two ago, my PC kept suddenly rebooting. The solution I eventually came up with that fixed it was blowing compressed air through it in the back yard and getting all the dust bunnies out. Recently, while gaming my PC suddenly began crashing again. I got a new graphics card, assuming the old one was getting too hot. The new GPU's fan doesn't even get hot enough for the fan to turn on before the PC suddenly reboots. So it seems the GPU isn't getting hot. I thought maybe the heat sink wasn't absorbing the heat well enough so I removed the old thermal paste and applied some new stuff. Still crashing. I thought maybe it was corrupted/malfunctioning RAM, so I ran Windows Memory Diagnostic. No errors detected. I've blown out all the dust bunnies, but according the my HWMonitor results, it doesn't seem to be getting hot. I'm not sure if my motherboard is crapping out on me or if it really is a cooling issue. It seems to not crash/reboot when I leave the window open and let the 30°F air drift in from outside, which leads me to believe somehow I'm missing some important temp numbers. I ran HW Monitor again today while running the CAD software that had caused the PC to crash just 5 minutes before and the temperature of my CPU never got above 45°Celsius (Max operating temperature for my CPU is around 71°C)

OH, another thing! I thought maybe something on my PC wasn't getting enough juice, so I bought a new power supply. I think it's 500W, more than my PC should need!

Attached are my HW Monitor results, please help!

CPUID HWMonitor Report
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Binaries
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HWMonitor version 1.3.0.0

Monitoring
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Mainboard Model 0G254H (0x0000015A - 0x004BC100)

LPCIO
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Hardware Monitors
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Hardware monitor NVIDIA NVAPI
Voltage 0 0.87 Volts [0x364] (VIN0)
Power 0 6.53 pc (GPU)
Temperature 0 20 degC (68 degF) [0x14] (TMPIN0)
Fan 0 0 RPM [0x0] (FANIN0)
Fan PWM 0 0 pc [0x0] (FANPWMIN0)
Clock Speed 0 135.00 MHz [0x87] (Graphics)
Clock Speed 1 405.00 MHz [0x87] (Memory)


Processors
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Number of processors 1
Number of threads 4

APICs
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Processor 0
-- Core 0
-- Thread 0 0
-- Core 1
-- Thread 0 1
-- Core 2
-- Thread 0 2
-- Core 3
-- Thread 0 3

Timers
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Perf timer 2.435 MHz
Sys timer 1.000 KHz


Processors Information
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Processor 1 ID = 0
Number of cores 4 (max 4)
Number of threads 4 (max 4)
Name Intel Core 2 Quad Q8300
Codename Yorkfield
Specification Intel(R) Core(TM)2 Quad CPU Q8300 @ 2.50GHz
Package (platform ID) Socket 775 LGA (0x4)
CPUID 6.7.A
Extended CPUID 6.17
Core Stepping R0
Technology 45 nm
TDP Limit 95.0 Watts
Core Speed 2493.8 MHz
Multiplier x Bus Speed 7.5 x 332.5 MHz
Rated Bus speed 1330.0 MHz
Stock frequency 2500 MHz
Instructions sets MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, EM64T
L1 Data cache 4 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache 4 x 32 KBytes, 8-way set associative, 64-byte line size
L2 cache 2 x 2048 KBytes, 8-way set associative, 64-byte line size
FID/VID Control yes
FID range 6.0x - 7.5x
Max VID 1.250 V



Temperature 0 39 degC (102 degF) (Core #0)
Temperature 1 33 degC (91 degF) (Core #1)
Temperature 2 33 degC (91 degF) (Core #2)
Temperature 3 33 degC (91 degF) (Core #3)
Clock Speed 0 2493.82 MHz (Core #0)
Clock Speed 1 2493.82 MHz (Core #1)
Clock Speed 2 1995.06 MHz (Core #2)
Clock Speed 3 2493.82 MHz (Core #3)


Thread dumps
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CPU Thread 0
APIC ID 0
Topology Processor ID 0, Core ID 0, Thread ID 0
Type 01008005h
Max CPUID level 0000000Dh
Max CPUID ext. level 80000008h
Cache descriptor Level 1, D, 32 KB, 1 thread(s)
Cache descriptor Level 1, I, 32 KB, 1 thread(s)
Cache descriptor Level 2, U, 2 MB, 2 thread(s)

CPUID
0x00000000 0x0000000D 0x756E6547 0x6C65746E 0x49656E69
0x00000001 0x0001067A 0x01040800 0x0C08E39D 0xBFEBFBFF
0x00000002 0x05B0B101 0x005657F0 0x00000000 0x2CB4307D
0x00000003 0x00000000 0x00000000 0x00000000 0x00000000
0x00000004 0x0C000121 0x01C0003F 0x0000003F 0x00000001
0x00000004 0x0C000122 0x01C0003F 0x0000003F 0x00000001
0x00000004 0x0C004143 0x01C0003F 0x00000FFF 0x00000001
0x00000005 0x00000040 0x00000040 0x00000003 0x00022220
0x00000006 0x00000001 0x00000002 0x00000003 0x00000000
0x00000007 0x00000000 0x00000000 0x00000000 0x00000000
0x00000008 0x00000400 0x00000000 0x00000000 0x00000000
0x00000009 0x00000000 0x00000000 0x00000000 0x00000000
0x0000000A 0x07280202 0x00000000 0x00000000 0x00000503
0x0000000C 0x00000000 0x00000000 0x00000000 0x00000000
0x0000000D 0x00000003 0x00000240 0x00000240 0x00000000
0x80000000 0x80000008 0x00000000 0x00000000 0x00000000
0x80000001 0x00000000 0x00000000 0x00000001 0x20100800
0x80000002 0x65746E49 0x2952286C 0x726F4320 0x4D542865
0x80000003 0x51203229 0x20646175 0x20555043 0x51202020
0x80000004 0x30303338 0x20402020 0x30352E32 0x007A4847
0x80000005 0x00000000 0x00000000 0x00000000 0x00000000
0x80000006 0x00000000 0x00000000 0x08006040 0x00000000
0x80000007 0x00000000 0x00000000 0x00000000 0x00000000
0x80000008 0x00003024 0x00000000 0x00000000 0x00000000

MSR 0x0000001B 0x00000000 0xFEE00900
MSR 0x00000017 0x08100000 0xAEC4C722
MSR 0x0000003F 0x00000000 0x00000000
MSR 0x000000CE 0x00164722 0x46460711
MSR 0x000001A0 0x00000040 0x6A872089
MSR 0x000000EE 0x00000000 0x86790B00
MSR 0x0000011E 0x00000000 0xBE702107
MSR 0x000000CD 0x00000000 0x80000A04
MSR 0x0000019C 0x00000000 0x883D0000
MSR 0x00000198 0x06164722 0x06004722
MSR 0x00000199 0x00000000 0x00004722


Storage
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Drive 0
Device Path \\?\scsi#disk&ven_hitachi&prod_hds721075kla330#4&36f1fef&0&000000#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}
Type Fixed
Name Hitachi HDS721075KLA330
Capacity 698.6 GB
SMART Support Yes
Volume c:\, 683.1 GBytes (65.7 percent available)
Volume d:\, 15.0 GBytes (51.2 percent available)

Drive 1
Device Path \\?\usbstor#disk&ven_teac&prod_usb___hs-ms_card&rev_4.12#00000118e05f&2#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}
Type Removable
Name TEAC USB HS-MS Card
SMART Support Yes

Drive 2
Device Path \\?\usbstor#disk&ven_teac&prod_usb___hs-cf_card&rev_4.12#00000118e05f&0#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}
Type Removable
Name TEAC USB HS-CF Card
SMART Support Yes

Drive 3
Device Path \\?\usbstor#disk&ven_teac&prod_usb___hs-xd#sm&rev_4.12#00000118e05f&1#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}
Type Removable
Name TEAC USB HS-xD/SM
SMART Support Yes

Drive 4
Device Path \\?\usbstor#disk&ven_teac&prod_usb___hs-sd_card&rev_4.12#00000118e05f&3#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}
Type Removable
Name TEAC USB HS-SD Card
SMART Support Yes

USB Devices
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USB Device USB Composite Device, class=0x00, subclass=0x00, vendor=0x0DBA, product=0x3000
USB Device Xbox 360 Controller for Windows, class=0xFF, subclass=0xFF, vendor=0x045E, product=0x028E
USB Device USB Input Device, class=0x00, subclass=0x00, vendor=0x413C, product=0x3016
USB Device NETGEAR WNDA4100 N900 Wireless Dual Band USB Adapter, class=0x00, subclass=0x00, vendor=0x0846, product=0x9012
USB Device USB Composite Device, class=0x00, subclass=0x00, vendor=0x04CA, product=0x0027
USB Device USB Mass Storage Device, class=0x00, subclass=0x00, vendor=0x0644, product=0x0200
USB Device USB Composite Device, class=0xEF, subclass=0x02, vendor=0x046D, product=0x0843

Graphic APIs
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API NVIDIA I/O
API NVIDIA NVAPI

Display Adapters
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Display adapter 0
Name NVIDIA GeForce GTX 950
Board Manufacturer EVGA Corp.
Revision A1
Codename GM206
Technology 28 nm
Memory type GDDR5
PCI device bus 1 (0x1), device 0 (0x0), function 0 (0x0)
Vendor ID 0x10DE (0x3842)
Model ID 0x1402 (0x2958)
Performance Level 0
Core clock 135.0 MHz
Memory clock 405.0 MHz


Monitor 0
Model Compaq WF1907 (Hewlett Packard)
ID HWP26A5
Serial CNC909NTWF
Manufacturing Date Week 9, Year 2009
Size 19.1 inches
Max Resolution 1440 x 900 @ 59 Hz
Horizontal Freq. Range 24-83 kHz
Vertical Freq. Range 50-76 Hz
Max Pixel Clock 140 MHz
Gamma Factor 2.2