Greetings.
I am not sure, but in mine, there is a power configuration, whereby, when I choose "Long-Life", the display dims.
I believe this is not the right way, because this should be used when you are running with battery, and you would prefer a slightly weaker performance to reduce battery consumption.

Never even heard of a Satellite 8250. Is this the newest, greatest, blah blah...? But I've got the same problem as you.

In many of the newer Toshiba's, there's no fiddling with the LCD's brightness - you can tone it down to semi-bright in the BIOS setup and that's about it (which will also require your processor to run at a slower speed). I have mine set to the dimmer settings. Hey, I prefer to keep my eyes...

I think that these damn screens are getting way too big for our own good. I just returned a brand new Dell last month 'cause my eyes were getting killed by its 15" LCD - too much screen. I'll be sticking with my older 13.3" units.