help my my external display

Hi.

I have had my macbook pro connected to my Optoma HD65 projector via the DVI out using a DVI to HDMI cable for over a year, without any problems.

Recently I connected my macbook again to the projector cable, but when it detected the external display, it recognized it as a VGA display. By the looks of the desktop background I saw when in mirror mode, I think the macbook thinks it is connected to my TV.

previous to the occurrence of the problem I had connected my MBP to my TV and it went into sleep mode and while sleeping I disconnected the DVI to VGA display adapter.

I read on various fora that this was bad for your MBP and I did a SMC reset and a Pro RAM reset. This did not work.

Then I did a full format of my HD and a clean install of OSX. This did not fix the problem, it still thinks a VGA display is connected when i hook up my projector.

please help!!

mac book pro original Mac OS X (10.6.5)