Second Monitor Blacks After Unlock?

I have a fujitsu t-series laptop running 32bit Enterprise. I use an Acer x163w for an external monitor. When the monitor is connect and the computer starts up, after I log in, both displays work fine for about 4 seconds then both go black and only the laptop display returns. The same behavior happens when I unlock my computer: both work for about 4 seconds, both go black, and only the laptop display returns (the Acer remains black). To fix this I have to do one of two things: 1 unplug and replug the vga cable from the back of the comp, or 2: reset my display settings to extend the display to the second monitor.