My mp3 says that i don't have anymore space, but it only shows 10

I'm not sure what you are asking, but maybe my experience can help you. I was using Windows 2000 (it has no DRM) and the Sansa C240 was displayed in Windows Explorer like a removable drive. I could copy and delete files in Windows Explorer. I switched to Windows XP and when I connected the C240, no files were displayed for it in Windows Explorer. I realized that XP had DRM and all the media files had to be transfered with Windows Media Player. When I opened WMP, it recognized the C240, but it didn't list any of the mp3 files I had already loaded on the C240. WMP asked if I wanted to delete all the media currently on the C240, but I clicked No. After that, WMP worked like the old files didn't exist. It would only delete files that had been copied to the C240 when it was synced.
I would recommend that you use Windows Media Player (or WinAmp) to delete all old media files on the C240 and use the sync button to copy and delete files from the C240. See Windows Media Player help for details.