Hello everyone.
i have a problem in cycles that the rendered image’s quality be bad and have noise . When raise the samples , the noises be lower but do not go 
what i do?
thanks .
There are lots of things you can do.
Read this article and the first comment of this article (by Thomas Dinges): http://www.blenderguru.com/4-easy-ways-to-speed-up-cycles/
If this doesn’t work don’t use cycles. Use Blender Internal. Cycles is still under development. Some things take a while to render without noise, still.
Or you can try to learn Mr. Bartek Skorupa’s technique of using bilateral blur in just the passes that contain the noise.
We need more information. What kind of scene are you trying to light? If it’s indoors or you have small lights, it is always going to take longer to clean up.
Dude, the thing is Cycles is a pregressive renderer. It keeps on rendering your image and calculating samples and passes until the image is clean. You can’t expect an instant clean render like the BI. And yes, it’s slow unless you use a GPU. I recommend you check out some Cycles tutorials on the net. The one that is on BlenderGuru is aweome. Check them out!
Cheers!