PC restarting by itself

[Flaming_Mook]

Hello,

About a month ago I bought and assembled my first ever gaming PC. However whenever I play Guild Wars 2 my PC sometimes restarts by itself usually in areas with high activity. I don't think it's a temperature problem since I downloaded a temperature reader and it all seemed cool on the inside. Could it be an issue w/ the power supply not being enough or a problem with the motherboard. Could it also be a problem with the outlet it's connected to?

My system specs are:

Window's 7 Home Premium 64 bit

Seagate Barracuda ST1000DM003 1TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMZ8GX3M2A1600C9B

Intel Pentium G2120 Ivy Bridge 3.1GHz LGA 1155 Dual-Core Desktop Processor BX80637G2120

Antec BP550 Plus 550W Continuous Power ATX12V V2.2 80 PLUS Certified Modular Active PFC Power Supply

XFX Double D FX-785A-CDFC Radeon HD 7850 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card

GIGABYTE GA-B75M-D3H LGA 1155 Intel B75 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard

Rosewill CHALLENGER Black Gaming ATX Mid Tower Computer Case, comes with Three Fans-1x Front Blue LED 120mm Fan, 1x Top 140mm Fan, 1x Rear 120mm Fan, option Fans-2x Side 120mm Fan

 

[alvine]

stress test your cpu using prime 95, have core temps to see the temperatures. if your system doesnt freeze/crash its not your cpu
benchmark your gpu by using furmark, if you dont see any graphical artifacts then its not your gpu either

550w is enough for your build

you can also check your ram for error by using memtest program (you have to burn and boot from the cd)