SanDisk Sansa c240 1gb driver problem for vista

I was given a sandisk sansa 1gb c240 model mp3/photo/voice recorder. it is a refurbished model and i was not given any installation discs. when i plug it into any usb port on my computer (with vista) the screen lights up and says that the battery is charging and when i go into "my computer" it is recognized under the "unspecified" category. i can browse the folders on the device, i can even play a voice recording i made in my windows media player. but when i try to put photos or music on the device it says that "the file has one or more properties outside of the device limits and may need a converter to function properly". i have tried running numerous searches on numerous search engines for drivers or software fixes and found no solution.