How to use a nextel data cable for a i850?

I bought a data cable for our nextel motorola i850 cell phones. How do I use it? It didn't come with a disk or instructions. I tried just plugging it in but my pc won't find it. I have Windows Vista So I am not to sure if there is a trick to it. I need to take my photos and songs off my phone broke and need to switch them to the new phone. Thanks for your time.
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