Screen freezes and BSODs.

This is very weird problem. I can't figure out what's causing it.

Usually, if I'm watching a Youtube video, and then I open a new tab, and I'm browsing something else while listening to the music my screen would first freeze up. And by freeze up, I don't mean in the usual sense. There would be many, many different coloured and tiny pixels all over the screen. For a little while I could even move my mouse, even though clicking anything doesn't work. And then I would have to restart the PC. That's the first case.

The second case is that I would be using my PC and then it just BSODs.

Now the weird thing is, I can play a graphically intense game - like Crysis, for literally hours, and nothing would happen. No BSODs, no freezes. I could watch full HD movies without this happening as well. It's almost always Youtube, and recently I noticed when I'm using Dreamscene as well.

I was using an XP until like last month. It used to happen on that as well. And then I bought Win7 x64. And it still happens.

Please help! Which part of the PC is causing this? I've attached the dmp file as well.

This is what it said on one of the error reports:

Problem signature:
Problem Event Name: BlueScreen
OS Version: 6.1.7600.2.0.0.768.3
Locale ID: 1033

Additional information about the problem:
BCCode: d1
BCP1: FFFFF88011E00000
BCP2: 0000000000000002
BCP3: 0000000000000001
BCP4: FFFFF8800F212BB0
OS Version: 6_1_7600
Service Pack: 0_0
Product: 768_1


I've run chkdsk multiple times with no errors. I've run the Windows memory diagnostic tool several times as well, choosing the most intensive options.

I have a single Kingston 800Mhz 2GB DDR2 stick.
450W PSU. Core 2 Duo E7400 Wolfdale 2.8Ghz.
nVidia DDR3 GT250 with 1GB vRam
Win7 x64
Intel DG41RQ MOBO