Are they all that way, or just some that you may have downloaded from the internet??. Frequently, internet downloaded MP3's have missing ID3 tags. If that's the case, there are a number of ID 3 "editors" which can be found by simply searching on Google.

But have you tried opening the folder where the files reside, then click on "View" in the upper left, choose "Details" from the list. Next, click on the "View" menu again and click on the "Choose Details" selection. You can configure the details which will be shown for your MP3 files.

Hope this helps.