Details needed... starting with brand/model camera, and the codec from the camera
Exactly what is INSIDE the video you are editing?
Codec & Format information, with 2 links inside for you to read http://forums.adobe.com/thread/1270588
Report back with the codec details of your file, use the programs below... A screen shot works well to SHOW people what you are doing
http://forums.adobe.com/thread/592070?tstart=30 for screen shot instructions
Free programs to get file information for PC/Mac http://mediaarea.net/en/MediaInfo/Download
What are you expecting to have - video with link audio or just an audio file? Any iTunes music involved here?
Where is your Premiere Elements 9 at this time, on Windows 7 64 bit or some place else? Are you running the 9.0.1 version? If not, please do so either
a. from the project's Help Menu/Update or from an online download
You say that, in Premiere Elements 9 on Windows 7 64 bit, your import is a file with a .mp3 file extension. Is that correct? What is the file extension before the import? When you drag that file to the Timeline, do you see content in only Audio 1 or rather in both Video 1 and Audio 1?
With the .mp3 at the Windows 7 hard drive save location, if you play it in Windows Media Player or any other computer player, do you see video and hear audio for that file even before the file ever sees your Premiere Elements 9 on Windows 7 64 bit project?
The smaller files will play using Windows Media Player but the largest files will not play.
Please define this smaller file....what is its duration and please confirm what the file extension is - mp3 or something else? Audio or Video or Both?.
Also please define this largest file...what duration and please confirm what the file extension is - mp3 or something else? Audio or Video or Both?
Lots to sort out but let us start here and then decide what direction to take after that.....like into Premiere Elements 9 on Windows XP, laptop failure, and the integrity of any projects and media associated with Premiere Elements in the Windows XP situation.