My sandisk says,"not enough space

"You need to format your device, the best recommendation is to place it into MSC mode. This is the Sansa's mass storage mode and it allows the device to be treated as a drive. Go to the settings menu and find USB Mode. There are two choices, MSC and MTP. Choose MSC. MTP is for music transfer using a media player software like Windows Media Player. If you don't have a way to set MSC mode with a menu on the device, engage the 'hold' switch, and while holding down the left or right button (others report also using the center button), plug the device into the USB connector. Make sure the USB is already plugged into the computer. You shouldn't need to do this with a standard e250; the menu should work. After you have connected the device in MSC mode, right click My Computer and choose Manage from the menu. Find Disk Management and select it. The disks should be numbered, starting with 0 for the C: drive. You should see a drive that says SANSA E250, or something similar. Write down the type of file system if it is shown. Most e250's says FAT32. Some are FAT, but check to be sure. There will be two partitions on the disk. The larger of the two is for your music files. The smaller is for when the device goes into "hibernation" - it's so you'll be back to the exact same song when it powers back on. Right click the larger partition and choose Format from the menu. You will see the format dialog. Set the volume label to SANSA E250 (I believe that's your device type), set the file system to what you wrote down earlier (do NOT choose NTFS!) and leave the Allocation unit size at "Default." Do not check either of the two check boxes. Click on OK. Keep an eye on the partition in Disk Management and you will see the percent complete. When it's done, look in the System Tray (by the date and time). You should see an icon for safely removing hardware. Double-click it to bring up the safely remove hardware dialog. Click on the USB drive representing your Sansa device and click Stop. Another dialog will come up and you'll have to do this again. Close the dialog when the device has stopped. The device will restart and initialize the music database. You're done! Now change to MTP mode and sync the device and add your songs back in. Whenever you are in MSC mode, ALWAYS stop the device as I described in the paragraph above. That way you won't corrupt the drive."
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