How to change resolution in Lion from 1080i?

[MyMac8MyPC]

I've moved my Mac into my living room so that I can use my HDTV as my monitor. Everything was going great except that the edges of the screen were cut off so you couldn't see the menus up top. So I went to change the resolution to 1080i (thinking it would make the screen slightly smaller) but all that happened is it turned the screen blue (I think the TV is doing this not seeing the Input). So I put the Mac into safe mode and changed the resolution to 1080P, but when I reboot and it gets to the password login screen, the screen reverts to blue again

How can I change the resolution to 1080P and have it stay there?

I'm using the latest version of Lion. Thanks for any help/suggestions in resolving this matter.

[chscag]

Which Mac do you have? Year, model? If it's a notebook (MacBook or MacBook Pro) you'll need to operate in clamshell mode to obtain the correct resolution on the TV.

[MyMac8MyPC]

It's a new Mac mini (about a year old). Whatever their top model at the time was. When I was in safe mode I was able to fix the issue with it not fitting on the screen properly. There is an adjustment for overscan. I just need to be able to get rid of the blue screen (change the 1080i setting) and it should be golden.

[chscag]

Try resetting the PRAM as that controls monitor depth. Also, if your TV has a factory restore setting (as some monitors do) try that. But it really sounds like your Mini has "memorized" the 1080i setting. If that's true, resetting the PRAM should fix it.