CD burning problems

I download to my PC the audio and then burn either in WMP and a couple in Nero 8. When I play the burned CD towards the end of the CD the audio chatters, skips or cuts off before the finish. I have enough time left before the 80 minutes are done. At time up to 30 or 40 minutes. I don't know where to even begin except that when I play the original all the audio is there. Do you have any suggestions for me as to how I can correct this? Please advise and thank you in advance for any assistance.

Wadda