Alright Apple product experts, got a problem/question for you

Almost posted this on the OT, but the board ain't really in my neck of the woods. So help me out here music board:

I own a 160 GB old school Ipod

For many years I have loaded music onto that ipod from my external hard drive, which on my computer is drive E

I recently ran out of room on that hard drive and bought a new one which is drive F. Now, every time I download something try and put it on the Ipod, it doesn't work.

But, if I take that from drive F, delete something I don't need, and squeeze it on the drive E hard drive, it will go on the ipod

Anybody know what I can do to fix this problem? I want to just put stuff from my new drive onto the ipod, but it won't let me, it just sort of freezes up and the stuff shows up on the ipod but doesn't actually play. Any advice?