Can't remember how to go back to stock ROM

[18bmurphy]

I am running Apex Rom. I am thinking of going back to stock or at least something new. A month or so ago something happened to my SD card and everything was lost. So me being able to follow directions but not being a tech guy, I assume all my stock files are gone. So how do I go back to stock, I'm still rooted and all that stuff. Or maybe I should try a new ROM what do you all think.

Thanks

 

[18bmurphy]

By the way I have a Driod X