Every one of your minidumps is an 0x50 error. From auhma.org on this error:
0x00000050: PAGE_FAULT_IN_NONPAGED_AREA
Requested data was not in memory. An invalid system memory address was referenced. Defective memory (including main memory, L2 RAM cache, video RAM) or incompatible software (including remote control and antivirus software) might cause this Stop message, as may other hardware problems (e.g., incorrect SCSI termination or a flawed PCI card).
Four of the five dumps point to win32.exe as the probable cause but the problem with this read is that is way too general to give us anything specific.
The fifth one points to afd.sys but that too doesn't tell us much because that belongs to your MS operating system.
However, in the minidumps four times the process firefox.exe was listed. Many people have issues with the newer Firefox version (s). This could be your issue and what you listed as causing your BSODs they all have to do with online surfing, game playing, YouTube, etc.
One other process of significant note is the process ccapp.exe which is of Symantec (Norton). Here is some information I have found off the net:
ccapp.exe is a process belonging to Norton AntiVirus. It is responsible for the auto-protect and email checking facilities, both of which will not function correctly if this service is stopped. This program is important for the stable and secure running of your computer and should not be terminated.
Note: ccapp.exe could also be a process belonging to an advertising program by Symantec Common Client CC App. This process monitors your browsing habits and distributes the data back to the author's servers for analysis. This also prompts advertising popups. This process is a security risk and should be removed from your system.
* Note: I am just passing on what information I have found. I don't necessarily agree with removing anything unless I fully assured it is the right thing to do.
* Interesting isn't it that Norton Antivirus is also intitialized for web security.
* I would go to Symantec's website/forums and see what others have to say.
* I also wonder what FireFox users have to say about crashes of this nature.
* Lastly, I would definitely do a virus scan; there are much better security options than Norton. Try using Kaspersky's free online scan.