Try something like the following:
DisplayMode[] modes = Display.getAvailableDisplayModes();
booleas success = false;
for(int i = 0 ; i < modes.length && !success ; i++)
{
if(modes[i].width == 1024 && modes[i].height == 768)
{
try
{
Display.setDisplayMode(modes[i]);
success = true;
}
catch(LWJGLException e)
{
// Mode not supported
}
}
else
{
// Not interested in this mode
}
}
if(!success)
{
// Failed to set mode
}
else
{
// Display mode set! Hurrah!
}