New self-built PC experiences sporadic but persistent freezes with no error messages

[ZygalEta]

Hi, first time PC-builder and I was ecstatic when I was able to boot and use my new PC. However, I began experiencing consistent freezes (everything becomes unresponsive and stops moving - no error messages upon restart). I had suspected it was a memory issue and ran the Windows RAM diagnostic tool which did not detect any issues. This has occurred while using several programs, among which include Spotify, Microsoft Office, League of Legends, and browsing on Firefox and Chrome. I have followed the steps here: http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems but continue to experience the same issues. Is there any way of ascertaining the source of the freezes?

Build specifications:

CPU: Intel Pentium G860 3.0GHz Dual-Core Processor

Motherboard: ASRock B75M-DGS R2.0 Micro ATX LGA1155

Memory: Mushkin Essentials 4GB (1 x 4GB) DDR3-1333 Memory

Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive

Video Card: MSI Radeon HD 7770 GHz Edition 1GB Video Card

Case: NZXT Source 210 (White) ATX Mid Tower Case

Power Supply: Corsair Builder 430W 80 PLUS Bronze Certified ATX12V Power Supply

Optical DriveLG GH24NS95 DVD/CD Writer

EDIT: Sorry - forgot to mention that I'm running Windows 7 (64-bit)

 

[Outlander_04]

your operating system is?

 

[ZygalEta]

your operating system is?

Sorry, it is Windows 7 (added an edit to my op). I've also ran Memtest96 which reported no errors as well.

 

[Outlander_04]

Firstly start your PC in SAFEMODE . The screen will be low resolution but that should tell you if the problem is a windows driver . If it fixes the problem then you may just need to update mb chipset drivers [ that you installed from th disk that came with the mb ] and/or the graphics driver .
If that makes no difference then you can test whether the problem is windows software or your hardware by downloading Ubuntu linux .
This is a full free operating system . As you install it it will create a disk partition of its own and not disturb your windows installation .

http://www.ubuntu.com/download/desktop
choose the 13.04 and 64 bit options

When you reboot you will have the option of either windows or Ubuntu . Does the pc behave the same way with Ubuntu ?
If it does then the problem is hardware .

[ later you can get rid of the ubuntu installation and let windows take over that partition ]