So I have a dell 21in which has a VGA cable. I bought an adaptor for the mac to connect into the mini display port. Plugged it in, went to system preferences and it wouldn't detect. When the dell monitor is turned on it looks for input then it goes into power save mode (probably bc it cant connect). I tried resetting the PRAM, nothing. Tried restarting, plugging and unplugging cables, nothing. I have a late 2009 24in iMac. I'm beginning to believe that it might be the adaptor itself, but I've been reading that this is sort of a common problem with macs. Anyone have any suggestions on how to get this to work? Thanks in advance.