G5 monitor hookup

I'm (trying) to be a PC to MAC convert. I just purchased a refurbished G5 machine. It powers on and all, keyboard lights up, etc.

The monitor cable from my PC monitor is just VGA, but the MAC just has DVI connection. so I got a VGA to DVI adaptor, installed MAC to monitor via that, but no signal.

I doubt the new adaptor is bad, but is there some secret handshake I could be missing beyond this? Any assistance appreciated.

If the monitor has a DVI input, use that instead of trying to convert the DVI output from the G5 to VGA.