brightness pop up box appearing

[pilotlight]

A pop up box has started to appear in the centre of my screen approx. 4in. wide x 2 in. high. It is black in colour, and says ' brightness ' with a plus and minus sign at either end. My screen does not need any brightness adjustment.
The box appears at random and my cursor appears to go behind it if I try to click onto it.
The box usually disappears after one minute or so, but its presence is irritating.
Any ideas what is causing this, and more importantly, what do I do to get rid ?
Thanks for any help.

[rojash]

This is nowt to do with your PC! It's your monitor's on-screen menu display. Depending on the make and model of your monitor, you will have a number of buttons and/or rotary controls on the front which, when activated allow you to adjust such things as brightness, contrast etc. Sounds like either you are accidenatlly operating them (i've seen this done when someone had their keyboard very close to the monitor) or else one of the swithces is faulty.

[pilotlight]

rojash, thanks for that, the monitor is part of Dell Dimension 2400 series package, bought approx 4 years ago. Looking for my users instructions/fault finder as we speak.
Once again, thanks.