how ican install Ubuntu ?

hey any answer

it's easy. Do you have the CD?

Sounds simple I know. Install. And it IS simple. You put the CD in and follow the instructions. It's that simple. I have done this by downloading Ubuntu, burning the contents to a CD-R and running the disc on my pc. It's pretty straight forwad BUT I can't get the 64 bit version I downloaded to work. I put in the disc and it doesn't recognize it. So I requested a free 64-bit disc. You should do the same if you are having any problems. I am hoping that the file I downloaded was dead & I will have no problems once I have the disc. But anyways, don't worry about screwing anything up because Ubuntu walks you through the whole process. It's fantastic! And VERY easy! You will love it.
-Adam

Actually, there are few more things to consider.

1. How did you burn the CD? You have to do it a special way. See https://help.ubuntu.com/community/BurningIsoHowto

2. Did you verify the download? Bad download = bad CD. See above link for how to check the md5 sum.

3. Are you booting from the CD? Most of the time you have to enter your BIOS and set the computer to boot from the CD drive first. Otherwise you will simply reboot the computer normally.

4. Is the version you downloaded the correct version? Does your computer support a 64 bit OS? Are you one an Apple with a power PC CPU or something with Intel or AMD? Wrong version = no boot.