Won't charge or play, buttons don't work, screen flashes, clicks

Help! My poor old iPod Classic won't work, and I'm hoping it can be fixed...

For awhile I've received a message saying there is a hard drive error when I plug it into my PC - when I hit the do you want to fix it button, it doesn't fix it.

I managed to get the iPod into disk mode (plugged into PC with Windows 7) and now it's flashing and says do not disconnect... Any suggestions? If I reset it to factory settings I could presumably redownload my 2300 songs from iTunes, but have no idea how to reset it... Help!