Arduino Uno Overheating

I bought an Arduino Uno to use to control some LED strips. The set up looks kind of like this,

but made a few changes to make up for the fact that I am using a Uno instead of a Mega.

It was working fine for two days, then I went to plug it into my computer today and the leds on the board lit up for a second then faded dark. After a little more playing around I noticed the board was getting kind of warm on the bottom. So I searched around for the warmest spot, which was underneath the voltage regulator. I put my finger on it and plugged it in, and boy did it heat up fast. Almost to the point of burning my finger. I am just going to guess that this is the problem. What would cause this? How can I prevent this in the future? Thanks!

You have to read the manual of that device. Look for V+ requeriment on voltage and current. Also I'd use transistors on each pin output instead connecting them directly because it may exced 35mA.

PLEASE resize that picture. It completely fucks up my browsers.
No more than 1000 pixels on the longest side, thanks.

Also, what does the specification for the "LED amplifier" state about the inputs?

If you don't have any documentation, open the box and take a good, clear picture of the internals. Resize the picture o maximum 1000 pixels on the longest side, and post it here.

// Per.