Problem between computers and device.

I bought my (m250) mp3 player last year i think, and i had a Dell with XP on it. Well, i put songs on it using that computer, and now i have a new computer, HP with Vista, And it will let me add songs, but i cant get to the songs that were already on my MP3 player form the other computer, even though they are on the MP3 player, why can i not accecss them from my new computer?

Did you happen to transfer the tunes from your old computer in a
different mode than the player is in now? Try switching modes
and see if you can see them.

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