Help: Frequent Blue Screen

I have a Windows 7 Home Premium 64 bit OS installed on my computer. Recently, my computer has experienced very frequent bluescreen, with the information provided as follows:

Problem signature:
Problem Event Name: BlueScreen
OS Version: 6.1.7600.2.0.0.768.3
Locale ID: 2057

Additional information about the problem:
BCCode: 7f
BCP1: 0000000000000008
BCP2: 0000000080050031
BCP3: 00000000000006F8
BCP4: FFFFF800032D0D91
OS Version: 6_1_7600
Service Pack: 0_0
Product: 768_1

The above problem happens more frequently when I use cable to connect to the internet than using wireless internet, and more frequently with a video chatting than without it. Not sure whether there are any connections between the problem, wireless internet and video chatting.

Surprisingly, I don't have the permission to upload the dump file, although I am the only user of the computer.

Is there anyone here can help me... I am driven mad by this stupid problem.... Thank you in advance.

By the way, the problem only appears recently (within 10 days or so), and I have used this computer for nearly 3 months. I didn't change any configurations recently, except installed some updates of Windows downloaded from the microsoft website.

Additional information:

My Windows 7 is:
- x64
- original installed OS on the system
- an OEM

- What is the age of system (hardware)? 3 months
- What is the age of OS installation (have you re-installed the OS?) 3 months, no I haven't re-install it.