If you upload a file to MediaFire and create a free account or log in to your account before uploading a file, then that file will appear on your My Files page.

If you don't create a free account and you lose the sharing URL for a file you uploaded, then unfortunately you'll need to upload the file again.

For this reason, we highly recommend that you create a free account so you'll always be able to manage and share the files and images that you upload to MediaFire at any time from any computer just by logging in to your account.

Please see http://support.mediafire.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=26 for more info.