BSOD at random times when closing pc or closing browser/applications

Since a few weeks ago after I installed Windows 7 x64 I keep on getting random BSOD but not frequently (number of 3). First one I really didnt paid attention how it happen but the second one was after exiting a game of Counter Strike Global Offensive and entering teamspeak to talk after a few seconds BSOD. The last one i got i searched on the web how to find the error and i manage to get the file and the error state.

The bugcheck was: 0x00000050 (0xfffff900c5844cf0, 0x0000000000000000, 0xfffff9600031c69d, 0x0000000000000000).

I uploaded the file and i manage to locate the other ones.

Event[3809]:
Log Name: System
Source: Microsoft-Windows-WER-SystemErrorReporting
Date: 2014-09-14T09:53:28.000
Event ID: 1001
Task: N/A
Level: Error
Opcode: N/A
Keyword: Classic
User: N/A
User Name: N/A
Computer: Alex-PC
Description:
The computer has rebooted from a bugcheck. The bugcheck was: 0x00000050 (0xfffff900c2c4b030, 0x0000000000000000, 0xfffff960002ec69d, 0x0000000000000000). A dump was saved in: C:\Windows\MEMORY.DMP. Report Id: 091414-5772-01.

(THIS IS THE ERROR I DONT REMEMBER WHAT I WAS DOING EXACTLY BUT DEFINITLY NOT GAMING , MAYBE EDITING OR SURFING THE WEB)

Event[7789]:
Log Name: System
Source: Microsoft-Windows-WER-SystemErrorReporting
Date: 2014-09-28T15:02:59.000
Event ID: 1001
Task: N/A
Level: Error
Opcode: N/A
Keyword: Classic
User: N/A
User Name: N/A
Computer: Alex-PC
Description:
The computer has rebooted from a bugcheck. The bugcheck was: 0x0000003b (0x00000000c0000005, 0xfffff8000303e01e, 0xfffff8800c10bde0, 0x0000000000000000).

(THIS ONE HAPPENED AFTER I FINISHED THE GAME AND THEN SWITCHED TO TEAMSPEAK TO TALK TO SOME FRIENDS WHILE TALKING THE ERROR OCCURED)

PS: I talked to a friend after the error and he said that i should reinstall the video graphics because that could be the problem so i did that too unistalled it then installed the newest version but still another error yesterday.

Event[9094]:
Log Name: System
Source: Microsoft-Windows-WER-SystemErrorReporting
Date: 2014-10-01T02:10:04.000
Event ID: 1001
Task: N/A
Level: Error
Opcode: N/A
Keyword: Classic
User: N/A
User Name: N/A
Computer: Alex-PC
Description:
The computer has rebooted from a bugcheck. The bugcheck was: 0x00000050 (0xfffff900c5844cf0, 0x0000000000000000, 0xfffff9600031c69d, 0x0000000000000000). A dump was saved in: C:\Windows\MEMORY.DMP. Report Id: 100114-11294-01.

(THIS HAPPENED YESTERDAY AFTER I WAS DONE SURFING THE WEB ON CHROME I DECIDED TO GO TO SLEEP SO WHEN I TRY TO CLICK CLOSE CHROME THE ERROR OCCURED)


Btw i noticed that sometimes my browser crashes while trying to save like pictures and sometimes even my windows explorer stop responding so i have to like click close now and then it does the windows sound and it restarts like the explorer but all the applications still running.

Thanks again for the support!

I see , but can you tell me at least why the errors occured? what can be the cause of it?