BSOD while doing random stuff.

I have had this PC for 4 years now, it's specs are
3GB of RAM
Intel Processor - Dual Core - 2.13 2.13
And the graphics card
ATI Radeon HD 4650

I've recently installed windows 7 x64 bit, in plans of installing 4 more GBs of RAM.
That happened yesterday. I've installed everything,some windows updates and everything went smoothly.
I've dowloaded some documents and pictures from the party a few days ago and they were in a .rar file.
Upon trying to unrar them with a WinRAR, my computer blue screened. It firstly did a freeze,then a grey-ish screen with blue stripes,then immidiately restarted.
I thought-hey new windows that had to happen. So.. After redoing the process, trying to unrar the files again, my pc blue-screens in a minute.
But this time with a white screen,then just restarting.
I downloaded 7zip and unzipped it with that program,everything worked dandily.
Today. The computer unexpectedly blue-screened 3 times, every time with a new method.
First time I was watching some youtube and it just suddenly froze with a black screen with blue stripes on it, then proceeded on restarting.
Next time I was scrolling facebook, then it just blue-screened.
And this time I was downloading games from Steam.


The output of the PC after BSOD:
Problem signature:
Problem Event Name: BlueScreen
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 1050

Additional information about the problem:
BCCode: 100000ea
BCP1: FFFFFA8003EE0B60
BCP2: 0000000000000000
BCP3: 0000000000000000
BCP4: 0000000000000000
OS Version: 6_1_7600
Service Pack: 0_0
Product: 256_1
The optional things:
Files that help describe the problem:
C:\Windows\Minidump\051015-16161-01.dmp
C:\Users\Marko\AppData\Local\Temp\WER-33509-0.sysdata.xml

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_______________________Thank you guys so much in advance.

Here's the file:

~Got some more info about this.
Whenever I watch youtube it crashes my computer. Not every single time. But for example when I watch Scott Manley, there's a 75% chance I'll get BSOD.
It's the same with every other youtube video
Helpp meeeh :/

The drivers for my graphics card were causing the problem.
I've installed them, now everything works grand. I've installed service pack 1 and updated directx and flash.

BTW. Thanks for the help :)