Norton Internet Security has stopped working

I am using Windows 7. Today is 26 May, 2014 -- for the last 2 days, I've been getting a daily alert that "Norton Internet Security has stopped working." When this happened yesterday, I rebooted my computer and all was well for about 1.5 days. Then, today, it happened again. 

 

Here are the details of the alert box:

 

Problem signature:
Problem Event Name: BEX
Application Name: NIS.exe
Application Version: 12.11.2.9
Application Timestamp: 5355938e
Fault Module Name: StackHash_0a9e
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Offset: 00000000
Exception Code: c0000005
Exception Data: 00000008
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 1033
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789