Suddenly, most songs I download are in the form of a "document" that quicktime can't recognize until I convert it. Because of this I can't launch these items or I'm assuming burn them ? any clues ?

Have you tried rebuilding your desktop?
Also, I read in a thread that in some OS's other than OSX, a very, very long filename would result in the filename getting automatically truncated which would eliminate the file's extension, making the Finder unable to recognize what type of file it is, thus making it appear as a blank document.
Try shortening the name (if it is really really long).

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iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-

I forgot: what format do you dld? .mp3?
That file format should (of course) be recognized by Quicktime but others like .m4a and .ogg or .wma I'm not too sure about (actually, I know for sure that .wma is not playable by Quicktime...)

__________________
iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-

Thanks for your response. I tried rebuilding my desktop. I was very encouraged when the first sample I launched worked fine but after that the problem came back. It wasn't a problem at all for a long time, just started one day. Does it have anything to do with the amount of music I have downloaded (25 songs) - a memory issue ? Or is it something that is being experienced by others lately ? I miss being able to launch a small portion of the song to see what it really is. Any more ideas out there would be appreciated.

Which OS version do you have? I'm guessing it's not OSX. No. of dwnlded songs shouldn't make any diff. How much ram & cpu do you have? Is QT the only app you have to play mp3's? Keep in mind that there's all types of mp3's that require different codecs to play as murasame suggested. Some QT can't play. What type of icon do these files have? Do they have the .mp3 extension?