Won't Charge or do anything! Please Help!

Well, I got this iPod classic thin 160gb from a friend and he told me that it had not been working and he had no idea what was wrong with it. After researching a little, I saw that replacing the battery seems like a common answer so I went ahead and ordered one. Well, while I was waiting for the new battery to come in I saw that there were these yellow dots on the screen, so I figured why not order a new screen and replace it too.

Well, I took apart the iPod and got the old battery out and took out the screen and that yellow liquid was on the lcd screen and on the blue foam on the hard drive. Any ideas on what that might be?

Well, I installed the 2 new parts in hope that it would fix it and it didn't. Nothing at all will show up even when I press the center and menu button. I charged it for a while and tried it a wall outlet and on a computer and still no response. I've also tried disconnecting the battery and hard drive and reconnecting, but still nothing.

The inside of the charge ports look normal and the cord works on other ipods.

Any help would be appreciated! Sorry about the lengthy post!

Edit: Should I buy a new logic board or HDD? I'm pretty willing to restore it, but just want to save money if I can!