BSOD after opening program (windows 7 64bit)

I would like for someone to check out my BSOD info for me, please. I've included the necessary attachments.

The BSOD occurred when I tried to open a game called Puzzle Quest 2.
I had Yahoo Messenger and Firefox (and possibly Winamp) also running at the time.
I have opened and played this game many times before, likely with the same other programs open too, so I've no idea what went wrong.
The problem has not repeated itself tonight, yet.
This is also the very first BSOD my system has had.

I have a Windows 7 home premium x64 system.
It is the original OEM pre-installed system that was included on my HP/Compaq CQ5201F, and it has never been un- or re-installed.
The system is dated August 26, 2009 according to the system specs website, although I bought it in late November '09/ early December '09.
Here is more detailed spec info if required:
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01859813&tmp_task=prodinfoCategory&lc=en&dlc=en&cc=us〈=en&product=4005896

The only hardware not originally included is an ATI Radeon HD 4650 video card, via PowerColor, and it was installed almost a month ago.
Here are its more detailed specs, too:
http://www.powercolor.com/global/pro...res.asp?id=244

In addition to the required BSOD info zip, I'll copy-paste the message that came up when windows restarted, in case that's of any use:

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: 50
BCP1: FFFFF900C00BF7A0
BCP2: 0000000000000000
BCP3: FFFFF9600061DC51
BCP4: 0000000000000000
OS Version: 6_1_7600
Service Pack: 0_0
Product: 768_1

Files that help describe the problem:
C:\Windows\Minidump\091410-17830-01.dmp
C:\Users\Seth\AppData\Local\Temp\WER-32401-0.sysdata.xml


Thank you for looking into this. I hope you find out what went wrong, so that I can avoid and/or fix the problem.

Thanks for checking this out.

It just so happens that winamp is acting weird with its media playlist and other things tonight, so I'm just going to reinstall.

Should I post to a new thread if I get another BSOD or keep it to this one?

Much to my dismay, I just had another BSOD last night. I had World of Warcraft, Firefox, and Yahoo Messenger open at the same time.

I have uploaded a new system info zip with the new mini-dump data. All my hardware is exactly the same as in my first post in this thread, so please refer to that.

The only notable software difference now is a copy of Bioshock installed. It has had its own crashes, but only going back to Windows, like most programs that glitch or freeze. I don't think it's related but it's worth mentioning.

These are the steps I took after this BSOD:

1) Full system virus scan with Norton Internet Security 2010 in safe mode. Nothing.
2) Restart with a pre-windows-load memory diagnostics. Nothing.
3)Ran Defraggler program (did NOT defrag last time) and found 20% fragmented hard drive ! So I let that run for several hours, and now that part is cleaned up.

I have my fingers crossed, hoping that the defragmenting is what I needed. Is a badly fragmented hardrive a reason for BSOD sometimes?

A friend of mine said so anyway, and told me that because I found something to fix, I did not use the RESTORE option like last time. Still, I want to know why this happened, so I appreciate you guys looking into it again.

I'll include the message that popped up right after BSOD again, just in case:

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: 3b
BCP1: 00000000C0000005
BCP2: FFFFF960001B4377
BCP3: FFFFF88006343070
BCP4: 0000000000000000
OS Version: 6_1_7600
Service Pack: 0_0
Product: 768_1

Files that help describe the problem:
C:\Windows\Minidump\092210-37518-01.dmp
C:\Users\Seth\AppData\Local\Temp\WER-58469-0.sysdata.xml

BUMP!

Please can someone check this 2nd BSOD out?