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Probably caused by: BHDrvx64.sys = Symantec Heuristics Driver
Please upload your msinfo32.nfo file. To get this: Start Menu -> Type msinfo32 into the Search programs and files box -> When it opens, go to File, Save -> Save as msinfo32.nfo and save in a place you will remember -> Let it finish the process of gathering and saving the system info -> Right click the .nfo file, click send to compressed (zipped) folder -> Upload the .zip file here.
Norton is a cause of BSOD-s alone, uninstall it and replace it with Microsoft Security Essentials (TO TEST)
Recommended antivirus program for Windows 7 based on stability compared to others:-
Do not start the free trial of Malware Bytes; remember to deselect that option when prompted.
Run a full scan with both (separately) once downloaded, installed and updated.