Try this solution:
Make sure your computer meets the system requirements for iPod mini(http://docs.info.apple.com/article.html?artnum=93633). Connecting your iPod mini to a PC that has older iPod software on it can cause this symptom.
Macintosh users should use the FireWire cable to connect to the computer. With Mac OS X 10.3.4 or later, you can also use a high-powered USB 2.0 cable if your computer has a USB 2.0 port.
Put iPod mini into disk mode(http://docs.info.apple.com/article.html?artnum=93651). If you can see iPod on the desktop, in My Computer, or in iTunes now, you're ready to restore(http://docs.info.apple.com/article.html?artnum=60983) it. If you have an iPod mini and are using it with a PC, try restoring the iPod mini even if it won't go into disk mode.
Warning: Restoring iPod erases and reformats the hard disk. All music and other data on iPod will be erased. Make a backup of any files or music on iPod before restoring it.
If you can't put your iPod into disk mode, reset it(http://docs.info.apple.com/article.html?artnum=61705).
Hope this information helps.
I connected my ipod mini to my computer, but it does not appear in the itune, i download the ipod updater put my computer does not read DMG files, how can I transfer music on to my ipod again? By the way, I can't use my cd-rom so it's impossible to install it from cd.