to rename them all into the lower case extension requires you to go old school = ]
Click on start -> run -> type in "cmd" without the ""
Now that you have brought up MS-DOS, we will have to navigate to where your files are. Put your mp3 files into a convenient location such as creating a folder on the root of your hard drive. The reason for this is that the MS-DOS window will be very cluttered when you navigate through all the sub menus and eveything.
So in my case, i have 4 mp3 files all in upper case extension .MP3. And i created a folder called "Upper case" to hold them on the root of my C: drive.
so i type the following commands in DOS-
cd c:\upper case
this command will take us to the directory with the 4 mp3 files.
to list the files so that DOS can see them type-
dir
Now, all the files in that directory should be listed, in this case there will be 4 mp3 files.
Finally, its time to rename them, type in the following command-
ren *.MP3* *.bak
this command will change all the file types that ends in .MP3 to .bak. The .bak extension is just a placeholder for us to revert the .MP3 to .mp3 extension.
Now, we have to rename all the .bak extension back to .mp3
To do this, type in the following command-
ren *.bak* *.mp3 <---- make sure it is in lower case!!!
All your files should now be in lower case
This may sound complicated, but really its straight forward once you get the hang of it!
If you have any more problems about this, feel free to post back here