two monitors on Guadro FX 500/600

hi

I have a problem getting a second monitor to work on a Quadro FX 500/600. I can only see a 'no signal' blinking on the monitor. I already installed the latest nvidia driver and tried almost every option in the nview settings but I can only see one monitor. There is no option for a second one. Also tried switching the monitor on and off again. Attaching it before starting the PC, attaching it later, changed the DVI 2 VGA Adapter etc. I really don't know what to do next. Maybe someone has an idea that can help me