GMOD makes my computer turn off

These days, when I play Garry’s Mod, my computer will sometimes turn off for no apparent reason. The game doesn’t freeze, and there’s no blue screen of death, but the monitor turns off, followed by the computer itself. This doesn’t happen with any of my other games. I don’t know if GMOD just makes my comp overheat (it never feels particularly warm), it uses up too many resources, or what… has anyone else had this problem, or know how to fix it?

Pc Specs

List Addons

Condition: New

  Lifestyle:  	Gaming

  Operating Systems:  	Windows Vista Ultimate

  Startup Operating System:  	Microsoft® Windows® Vista Ultimate

  Platform:  	PC

  Form Factor:  	Tower

  Bays:  	1 - 3.5" Drive Bays
  	5 - 5.25" Drive Bays

  Internal Bays:  	5 - 3.5" Drive Bays

  Available 3.5" Drive Bays:  	1

  Available 5.25" Drive Bays:  	4

  Colors:  	Black

  PCI Slots (Total):  	2

  PCI Slots (Available):  	1

  PCI Express X1 Slots (Total):  	1

  PCI Express X1 Slots (Available):  	0

  PCI Express X16 Slots (Total):  	3

  PCI Express X16 Slots (Available):  	1

  Processor Brand:  	Intel

  Processor Class:  	Core i7

  Processor Number:  	I7-920

  Processor Speed:  	2.66GHz

  Processors Supported:  	1

  Processors Onboard:  	1

  Memory Type:  	DDR3

  Memory Size:  	3 x 1024MB

  Total Memory:  	3.0GB

  Memory Speed:  	DDR3-1333

  Memory Slots (Total):  	6

  Memory Slots (Available):  	3

  Interface:  	SATA 3G

  Capacity:  	1TB

  Speed:  	7,200RPM

  Optical Drive Type:  	DVD±RW Dual Layer

  Optical Drive Class:  	DVD±RW DL

  Interface:  	SATA

  Audio Chipset:  	Intel High Definition (HD) Audio

  Graphics Description:  	Crossfire Mode

  GPU/VPU:  	ATI RADEON HD4850

  Video Memory:  	512MB

  Video Interface:  	2 DVI

  Interface Type:  	RJ-45 - Ethernet Connector

  Data Transfer Rate:  	Gigabit LAN

  Power:  	800 Watt

As for addons:

Adv Duplicator
Announcer
base
counter-strike
day-of-defeat
DearSister2
default_sent_pack
derma
dinosaurs
DPmedic
Extra_Npcs
Flashlight
food and kitchen
Greenscreen Materials
Half-Life_Renaissance
hl2_ep2
HL2_TF2_Style~A
Hook
JillValentine
Killer Croc
kitty pack UPDATE
L4D2 Models
L4D CMP2_1
l4dhunter
Lightsaber Pack v2
ls_pack
luger
Mario Hat v2
mechahydra
melonracer
MoonHead
Nude Medic
Paint Remover
Particle Maker
phx2
Pikmin
Pirate Hat
portal
Prop Resizer v2
pyro_girl
RE monster pack
redo
sandbox
Scout’s Mom
sentryposer
sfx
sk8r mega pack
skinswitcher
team-fortress
tf2
TF2 Oldschool Pack
Tf2_Spycloak
TRex
zeno_clash

Along with countless models/skins/etc. not in the addons folder.

Try cutting down that Berlin Wall of specs into the useful stuff: RAM, Processor, GPU

And have you tried a clean install? Simply rename your garrysmod folder to garrysmodold or something and launch the game.

hmmm, the fact that it makes your pc turn off makes two things come to mind right away, RAM (most likly cause) or a failing power supply. Try taking out all but one ram stick, start the game. If it runs alright try the next one, so on and so fourth until you find they one that is failing. RAM can be bad right off the line so it being new doesn’t really matter. Other then these two things I wouldn’t really know why it would shut your PC down. One thing I’m wondering about is this "(it never feels particularly warm), " you judge your cooling performance by touching the side of your pc?! Find some damn monitoring software for your MoBo and check the actual temps…

Check for overheating.