Ok, lets start by checking the ubuntu iso file.
1) Follow the instructions here https://help.ubuntu.com/community/HowToMD5SUM#MD5SUM on Windows://https://help.ubuntu.com/community/H...5SUM on Windows
to check the MD5 hash of the download.
If that checks out then make sure you're burning the disks properly (I've "coasterized" a couple dozen CD's and DVD's by not burning and iso proplerly)
2) Make sure you've selected "Burn As Image" or "Burn Image" and burn slowly (4x max, but i like 2X)
3) Once you've done that boot from the CD and chose "Check CD for Defects". it will run a few tests and spit out an answer if the CD is burned properly or not. It should restart your PC afterwards.
4) If all that checks out and you get the LiveCD to the desktop and it still freezes you may not have enough hardware to run the Live Install and may have to go to the Alternate Install disc" which is text based but still fairly easy to use The system requirements can be found here at the top of the page http://www.ubuntu.com/getubuntu/releasenotes/910