Pixel format not accelerated.

[Brighter1]

Hello all, I am looking for a solution to an error my boys get when trying to play minecraft.  It started about a week ago and I can't seem to figure it out.  They were playing the game as usual that morning and then something happened or someone did something and now we get the error:
org.lwjgl.LWJGLException:Pixel Format not accelerated

I have looked at the forums, but nothing has been able to help me.  I am not very good with computers so of course that doesn't help.  I have posted on 3 different sites with no help at all.  I will answer all of your questions, but you might have to tell me where to find any info needed.  Any help would be greatly appreciated by me and my boys.  Thank you in advance.
I have an HP with Windows XP.

Bree

[kappa]

this error usually means that opengl can not be found or started, its possible that your graphics cards drivers may have been changed or broken in some way.

You might want to try reinstall your graphics drivers or return in to default settings.

[Brighter1]

how do I change it to default settings?  I am thinking that my youngest might have done something since it was working earlier in the day.  Thank you for your thoughts on this.

[broumbroum]

reload you hardware drivers with the certified ones !

[kappa]

yup, like if you have a nvidia card, go to the nvidia website and download the latest drivers for your video card and install it.