Fullfixed=TRUE
Fullresolution=1024x768 (default)

Under dosbox.conf

😎

okay, that fixed the off center problem, but now the actual "game screen" is really small with black boarders on all sides, I'd say it turned my 19 inch screen into a 9 inch screen, is there a way to fix that ?

Read the docs and try tinkering with the various video parameters inside DOSBox configuration file.

Aspect=true (or vice-versa)
hwscale=1.0
output=xxxx

Either turn the resolution down, or increase the hwscale or scaler settings in dosbox.conf.

Hi, i am having the same problem that the other guy spoke of where dosbox comes up off-centre when in fullscreen mode. I did that 'fullfixed=true' thing but like the other guy said this just makes the display really tiny in full screen mode. I then tried to follow the second bit of advice given which was to change aspect to true, and then to make output=xxx, which i interpreted to mean change it to all the things possible and see if it works. Anyway when I change the output to equal 'overlay' and 'ddraw' it comes up as a good size in full screen mode without the edges cut off, however this leads to other problems. When using 'overlay', the game runs incredibly slow and is really jerky and is unplayable. When using 'ddraw', the games run at the normal speed but the screen becomes mega blurry. So anyway I was just wondering if there is another fix to this problem that doesn't affect the performance of dosbox, or whether there is an easy fix to the additional problems i ran into. And should somebody respond can they please use layman's terms cos I am not really that brilliant with computers.

well the offcenter when dosbox goes to full screen is NOT a bug of dosbox.
but it just your monitor which isn't correctly calibrated at the new screen size.

Fullfixed is to work around of that. by keeping your original resolution thereby your monitor doesn't have to adapt.
In short press auto-calibrate or get a better monitor.
My 17 inch FTF can switch to fullscreen fine.

its ok. I have it working now. When I was playing around with the aspect and output before I still had fullfixed=true and when I changed this back to false all I had to do was change aspect to true, and leave the output on surface. I now see the whole dosbox screen and nothing gets cut off. It is a little bit smaller than my actual screen and consequently there are some thin black regions around the edges but its really not that bad at all.