all of my songs on my iPod touch are not syncing to my iTunes library

I have 2 iPods (Gen 2 if not mistaken) and I want to get all the music off
of them but it only gets my "purchased" items... but I need all
the rest. I would just get the music again however the HDD I had
everything stored on was mistakenly never backed up and the server
completely crashed - everything was lost and I am so super upset.
Adding more fuel, this is not the same computer I started using iTunes on
if that even makes a difference.

When I look at the songs (while iPod is connected to iTunes) all the boxes
are checked HOWEVER they are grayed out so I cannot check/uncheck anything but
even though they are checked they do not go over into my iTunes library.

I have lost about 75 GB's of music - these iPods are all I have left -
please someone say there is something that can be done to get them sent in the
library.

Thanks in advance for anyone that can assist!!!