Toshiba Fn plus the up/down keys adjusts system volume sound levels. Fn plus function keys F5&F6 has little pictures of suns on them here and does the display brightness. But I think to make it the light level stick you have to use the Control Panel 'Power Options' ... at least on my Toshiba is the way it seems to work.

Thank you so much. Actually, I did not have to look at much. One of the links was concerning a dimming problem, but it was a more serious problem than mine, as they tried everything, without success. However, in the discussions, they referenced the dimming and brightening keys on the keyboard. I had no idea of their existence. Sure enough, I found them and that was the problem. I must have hit them, when I was fumbling for another key. The keyboard is a wireless, which came with the purchase of the iMac, and it's about 1/2 the size. Very nice for a hunt and peck typist like me, much easier to use, as my peripheral vision sees the whole panel. Also, I can use it off my lap while I lean back on my reclining chair. Thanks again, I now see the light!!

Thanks for your support peewee and don. If peewee does help people on this forum well that is good, but don't insult me by telling me to do something that any normal person would do. He could have asked if I'd turned down the brightness, but he didn't. If it was just a case of turning down the brightness I wouldn't have come to this forum in the first place. It's always nice to hear from idiots like you, don. For your information I don't enjoy being treated like an idiot as the peewee did when he answered my question with his one lined response. I think you are the reason people are driven away from this forum. How many others have you men(I can only assume you to be one after all with a name like don...but then I am only an idiot after all) treated like morons and then accused them of being the case of some rift? I have found some other knowledgeable people who answered my questions about my TV without considering me to be an idiot. Don't let the keyboard come up to bite your arrogant ass. Oh wait, go ahead let it.

Thanks for the ceiling light panel suggestion. That's an easy one to get in large sizes that I can cut myself. I don't have any other surface to put plants on except windowsills. I have Phalaenopsis, Vanda, amaryllis, several succulents, African violets, Pothos, Dracaena, Croton, Peperomia, Tillandsia, Peace Lily, etc. They do well most of the year but, some days during the summer (fortunately, summer in Chicago is very short!!!) are especially bright and hot for them. Some of them are older plants (3+ YO), some are new replants (I trim/repot throughout the year as needed).