Hello, I plan to buy a mini DVI to VGA adapter (already bought mini DVI to DVI adapter and it wasn't the right one ). Once I do this, how can I use my second monitor in Extended Desktop mode? Where do I turn it on? Thanks. P.S. When I took the moniter from my brother's PC I noticed it did not have a power cord attached, I guess it got its power from the PC, will this be ok with my iMac?