EX64.SYS and the BSOD

Since yesterday, I have been getting a great many BSODs. The major problem seems to be the EX64.SYS file. Here is a copy of the minidump:  https://onedrive.live.com/redir?resid=D284746392A71327!1627&authkey=!AInjoDPCba1Jbr0&ithint=folder%2czip

I got the computer in the Summer and have only ever used Norton as the anti-virus program. 

Any suggestions?  Thank you.