question concerning uploading beats via usb

i recently purchased a mpc500, i already have a few drum kits & samples. the problem i'm having is uploading my finished beats onto my pc. when i try playing the midi. files, it only plays the drums & no samples. it doesn't sound anything like when i play it on the mpc. do i need a specific program to read the files properly or do i need to save my sequences/songs into a different format? what am i doing wrong & how can i save my beats in mp3 format?

sorry if this has been adressed before, i used the search & couldn't find anything to help me out. thnx.

ok my bad, i found a thread that answered my question, u can delete this one. thanks.