Personally Owned Music from My Library Doesn't ...

Hi there!

I have a pretty extensive library of music that I've uploaded to iTunes on my Windows system. I have no problem accessing any of it as long as I'm on the computer on which I created it, but I cannot access ANY of them on my laptop (also Windows). I've (obviously) downloaded iTunes, have authorized the system, but nada. I know it's something I'm not doing...any suggestions?

Thank you in advance!