St. John's Group Email I need some computer help

Hey my computer literate friends,
 
My computer has several user accounts, one of which I use most frequently. 
 
At this moment it is not listed when I log on and I am not able to find it.  Yet I know it is there because when I tried to create a new account with the same name it said it allready existed. 
 
How do I get to my user account? 
 
Thanks for your help.