Change Laptop Screen Brightness

[countrykid]

I want to adjust the screen brightness on my 2 year old Toshiba Laptop which runs Windows 8.1. I have done this in the past I'm sure, by using the up/down button on the keyboard that have a "sun" symbol on. Nothing happened when I pressed those, so I went into Control Panel, clicked on Appearances and selected change brightness. I was able to move the slider, but it made no difference to the brightness of the display. I am puzzled as to why.

Just for the record, the volume button on the keyboard work fine. Thanks

[Zacs-Master]

Have you tried holding down 'Fn' and tapping the 'sun' symbol?

[countrykid]

Hi Zacs-Master, yes I meant to say I have tried holding down the FN key but no luck with that either

[Zacs-Master]

Try Fn key with F7 or F8.

[countrykid]

F7 and F8 on my pc have allow you to do something relating to "caret browsing" whatever that is. On my keyboard the sun symbols are on F2 and F3

[countrykid]

Further info - I pulled out the mains lead and the screen went really dim. I plugged the lead back in but the screen remained dim. Battery is fully charged by the way. Could it be that the pc has gone into some eco or power save mode? If so how do I change this? Thanks

[countrykid]

This is really driving me crazy!!! In my attempts to solve this problem I have discovered that if I switch the laptop off, on rebooting the display is nice and bright with the mains lead OUT. If I then plug the lead in, the display darkens. Unplugging then makes no difference. I have checked the power setting and went into "change the plan" and the brightness level for both battery and mains is on maximum, even though the actual display is dim. I have no idea what else I can do. The bottom line is that I have no control now over the display brightness, whereas before I could adjust it using the two keyboard button for + - dependent on what I was viewing. I just want to have that control back. Can anyone help? Thanks in advance

[countrykid]

Sorry Methyl, only just seen your response. The model is Satellite C50D-A-12U. Since my last post I can report that the laptop really has a mind of its own. On booting up, it sometimes comes on with a bright display, other times its dim. Either way, it cannot then be adjusted. I feel certain that before this happened the, the F2 & F3 buttons that have the sun symbol on did allow the brightness to be adjusted when using the laptop. There is a facility on the PC for the F buttons to be operable without the need to press the Fn button, and this is activated. I'd really love to "fix" this without having to call a techie in, if only so that I can solve it again if it happens in the future.
I'll be able to check AB throughout the day for any responses. Any help is appreciated. Thanks

[countrykid]

I'd just like to update and say that for no known reason, the brightness buttons on the keyboard have suddenly started working again. I have not had anyone in to solve the problem or even attempt to, so no idea what the cause or solution was!!