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?