dvi/vga output not sending to second monitor

I just set up Pgbl single monitor docking station with my asus laptop, which was running windows 8. All backside functions worked fine, including dvi/vga connection to a separate monitor (as well as printer, external hard drive, mouse). But headphone output on the front was not sending to my wireless speaker setup. Downloaded Windows 8.1 and rebooted. Now speaker output works, but dvi/vga is not sending to second monitor. When I connect monitor VGA directly to my laptop, the extended display works fine. Connections for dvi/vga at docking station are as tight as I can get them. Thanks for any advice.