Playing Longer Online Videos Causes System Freeze - Windows 7 64 Pro?

Hello. I need your help! I do not know where to post this thread because the source of the issue cannot be verified.

I notice after playing long videos on You Tube and other websites, my screen will freeze-up for a few seconds and then unfreeze on its own at times. Other times I have to close out of the browser in order to get the system to unlock or I just have to wait a few seconds for the system to unlock on its own. Seems to happen only while playing longer videos online. Other than that, this issue does not happen. This is all new and started happening the last few days.

I will not elaborate too many details at the moment. It is best to take this step-by-step then throw lots of data out all at once and have many long paragraphs to initially post. Please ask me questions if you need too. I will tell you, I have run full system malware scans using Norton 360 and Malwarebytes Anti-Malware, nothing detected.


Some basic general stats of my system:
- Windows 7 Pro 64-Bit.
- Intel Core 2 Quad Q9550 -- Yorkfield 2.83 GHz 1333 MHz processor.
- ASUS P5Q desktop motherboard.
- 8 GB of Corsair XMS2 4x2 GB DDR2 RAM.
- XFX Radeon HD5670 Graphics Card.


Here are 2 Windows Critical Events:


Description
A problem with your video hardware caused Windows to stop working correctly.

Problem signature
Problem Event Name: LiveKernelEvent
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 1033

Extra information about the problem
BCCode: 117
BCP1: FFFFFA800CB0B4E0
BCP2: FFFFF880041953BC
BCP3: 0000000000000000
BCP4: 0000000000000000
OS Version: 6_1_7601
Service Pack: 1_0
Product: 256_1
Bucket ID: X64_0x117_Tdr:2_IMAGE_atikmpag.sys
Server information: d80fbc42-ef2f-4ae9-be5e-34b9b757f682

Problem signature
Problem Event Name: BlueScreen
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 1033

Extra information about the problem
BCCode: 119
BCP1: 0000000000000001
BCP2: 00000000FF000000
BCP3: 0000000000000000
BCP4: 0000000000000000
OS Version: 6_1_7601
Service Pack: 1_0
Product: 256_1
Bucket ID: X64_0x119_atikmpag!ProxyDxgkcbNotifyInterrupt+2d2
Server information: 4e983718-973d-44d5-89c3-0faa846760fb

Please help me and reply back.
Thanks!