I'm not sure if this is the right board for it, but I don't know where else to put it, please forgive me if I'm in error.

I have a Compaq Presario 2100 and it's working fine except whenever I plug in the AC Adapter the plastic around the uh.. plug? part of it starts melting. And so it gets difficult to detach from the computer, and after a while it stops working because the plastic is just, well, melted down. Even if I wait until everything cools down to detach the adapter from the lpatop, it still requires a lot of manuevering and yanking. I really really don't know what to do-- I thought it was just a problem with my previous adapter but I ordered a new one and it's still happening.

Am I doing something wrong, or is my computer malfunctioning, or is this supposed to happen?

It definitley sounds like you have a problem, it sounds like you have a short. If it's still under warranty have it checked by a factory authorized repair service, if not...you still need to have this repaired before it causes more poblems. If you take a nine volt battery and place a coin across the two terminals it will heat up to the point where it will be too hot to handle comfortably in a very short period of time, that's what that short is doing to your computer.

Sounds like you have a blown transformer. You need a new adapter! I had something like that happen with my laptop and I needed a new A/C adapter. Check these guys out:
<a href="http://www.12vadapters.com">12V Power Supply</a>