OK, so it seems that I need a dummy plug to be able to mine with my 2 6990s with Windows 7.

I have a monitor plugged in to one of the cards and that one is hashing away. The miner cannot detect / hash with the second one.

So here is my question. What happens if whilst the machine is mining I unplug the monitor from this one card and then plug it into the other one and then start those (or will my first one stop hashing the minute I unplug it)?

Second question: Eventually, there will be no monitors attached to the rig, I'll use logmein or vnc to get into it remotely. Does that mean I'll be needing 2 dummy plugs for both the cards?

Thanks for your help, folks!!