Randomly name files in my micro sd card

I have a 2GB micro sd card which I frequently insert in my headphones which can play/pause vol+/- and skip to next/previous mp3(only) songs with hard buttons. What my headphones cannot not do is shuffle the mp3 songs that I add and remove almost everyday in the sd card. So it plays from the same song every time I restart the headphones and I have to manually skip to next songs to get to a new song. By everyday use, I am pretty much sure that the headphones play songs in some alphabetical order but it is the same order of songs everyday. Can anyone please suggest me a software or code to randomly add a unique number or pair of letters in front of the already present mp3 songs in my micro sd card with just a few clicks so that I am free to listen to the shuffled songs on the go. The new name must contain the song name too so that it would be easy for me to delete old songs and add new ones.
Also, I am entirely not sure whether it chooses the song based on its name or memory location on card. Can memory locations be randomly changed for every file and it will it help in my case?
I use windows 7.