Screens go black after enabling surround

i have the following

 

gtx titan

 

2x benq g2420hdb 24" monitors

1 hd 42 inch tv

 

 

I was checking to see if this would work as i dont have any money for a third monitor. when i enabled surround all the 3 monitors went black. i had to restart pc. this happened everytime.

 

i made sure all the res on all three monitors is 60hz..

 

what am i missing or doing wrong?