No audio in mp4

Have been trying to play Mp4 files that I just recently downloaded from Youtube. The Video plays but no audio. I have older Mp4 files that play both video and audio perfectly. Here is the media info for both

The one with no audio-
General
Complete name : C:\Documents and Settings\david callaway\My Documents\My Videos\RealPlayer Downloads\Rob Zombie - Dead City Radio And The New Gods Of Supertown - YouTube.mp4
Format : dash
Codec ID : dash
File size : 14.8 MiB
Duration : 3mn 31s
Overall bit rate : 588 Kbps
Encoded date : UTC 2013-04-10 00:31:40
Tagged date : UTC 2013-04-10 00:31:40

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 3mn 31s
Bit rate mode : Constant
Bit rate : 585 Kbps
Width : 640 pixels
Height : 360 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 23.976 fps
Minimum frame rate : 23.974 fps
Maximum frame rate : 4 736.842 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.106
Stream size : 14.8 MiB (100%)
Encoded date : UTC 2013-04-10 00:31:40
Tagged date : UTC 2013-04-10 00:31:40

The one that works
General
Complete name : C:\Documents and Settings\david callaway\My Documents\My Videos\Stuff from youtube\Doctor Who\No. 10\Family of Blood Epilogue.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 12.3 MiB
Duration : 2mn 48s
Overall bit rate mode : Variable
Overall bit rate : 614 Kbps
Encoded date : UTC 2007-09-14 19:46:51
Tagged date : UTC 2007-09-14 19:46:51
gsst : 0
gstd : 168228
gssd : BADC21842MH1320986805266410
gshh : v2.nonxt6.c.youtube.com

Video
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L1.1
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 2mn 48s
Bit rate : 500 Kbps
Maximum bit rate : 1 236 Kbps
Width : 320 pixels
Height : 240 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 29.970 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.217
Stream size : 10.0 MiB (81%)
Title : (C) 2007 Google Inc. v06.24.2007.
Encoded date : UTC 2007-09-14 19:46:51
Tagged date : UTC 2007-09-14 19:46:51

Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 2mn 48s
Bit rate mode : Variable
Bit rate : 112 Kbps
Maximum bit rate : 125 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 2.24 MiB (18%)
Title : (C) 2007 Google Inc. v06.24.2007.
Encoded date : UTC 2007-09-14 19:46:51
Tagged date : UTC 2007-09-14 19:46:51

They both play fine on Youtube.

MediaInfo indicates that the file contains no audio. The problem is probably caused by your downloading tool. You should use a different one such as for example DownloadHelper plugin.