try reading one of the other threads here. I think there are 3 with your problem on the first page.

I have read through many threads here and in other forums. If I had found the answer I wouldn't be posting. The fullscreen problems in the other threads are not the same as I'm experiencing.

And what have you done to try to solve the problem? There is no point in us posting suggestions that you have already tried.

Yeah, you've got a point there.

I have tried changing the "fullresolution" line in dosbox.conf to many different resolutions. I have also tried changing the "aspect" line and tried all the available "scaler" options. I have spent hours trying different combinations of the above options and so far nothing works. The only difference I have noticed is that on some resolutions when Alt+Enter is hit DosBox closes!!??!

Thank you for taking the time to respond. This was supposed to be my easy project, setting up Samba is next but I think I might be out of my depth!!!!

The primary settings are the full-resolution and the output-methods. Scalers, aspect correction etc are secondary. I would set scaler=none, aspect=false to a start.

fullresolution should be set to the best, native resolution your monitor can handle. I am not sure about that PS3 + HDTV combination. Is it wide-screen? Maybe something like

fullresolution=800x600

will do? You could also try a "secret" setting

fullresolution=0x0

And then try that with different output methods.

fullresolution=1280x720
output=opengl # or openglnb if you like it sharp
aspect=true

Should give you a nice pillarboxed view. If you want it stretched then use fullresolution=960x720 or something 4:3 and have your display stretch it.