...of your music that was in your old iTunes library, then you will have to use a third party program to copy the files from the old iPod to your (newly loaded) hard drive, then import that data into the latest version of iTunes on your PC running W7.
There are some reviews of such software @ ilounge (and elsewhere)-
Just used irip to move music from a VERY old ipod to my Windows 7PC (songs had been in itunes but a virus forced me to wipe out the harddrive) and there was a problem. The automatic program suggested I move it to a folder in my music library instead then move it to itunes. Since I am a total technical neophyte, I don't know how to do that.