Setting up 3 different sized monitors.

So over the course of a few years I have gathered three different sized flatscreene monitors. I would like to have them set up with my pc but I can't get them to stay out of sleep mode, now this is the monitors going into sleep mode directly after telling me that they have no signal. My center monitor does stay on. The two that are not working are both HP brand , one is the 1907 model and the other is the 2009 model. The one in the center that works is a generic HD2200.

I have the 1907 setup with a VGA to dvi adapter. The 2009 is straight dvi, and the hd2200 ,the one that works, is through the hdmi port.
The card I'm using is an ati amd 6870.

I think that's everything. Thank you very much if you can help me.

Edit: I have decided to go with two for now instill I can track down a dvi to mini display cable.

Edit: ok so I unhooked them and tried them separately , I tried hooking the two HP's up one at a time with the hd2200 but while it worked on its own, once I plugged one of the HP's in both of them went black. So next I tried using my 32inch LCD tv as the main and then plugging the hp2009 in. The tv didn't go black, but neither did the second monitor turn on. The screen did flicker like mad though. Only when I put the resolution down to around 800x600 did the actual desktop show up.

I'm still trying to see what obscure phrasing of words will let google help me but I would also appreciate if anyone had some tips or anything.

And thank you to those who have already tried helping.