Saved where? You will have used iTunes to add the music to your iPod, so all that music should still be in your iTunes Library on your computer.
Open iTunes (on your computer) and see whether your music is listed there. If you have deleted your iTunes programme, the music would not have been deleted (unless you did so), so use Windows Explorer to look in the My Music folder. In there should be an iTunes folder and there will be an iTunes Media folder(or possibly iTunes Music). In this lowest sub-folder will be your music, arranged by artist and then album title.
Folders are: Music / iTunes \ iTunes Media \ <artist name> \ <album title> \ <song name>
Once you find that collection, you should ensure that you back it up, to prevent losing it if your computer fails.
If you have deleted iTunes, download it again and install it on your computer. iTunes - Apple