I have no idea what program is causing it or what starts it, but it's happened a few times now where I'll be working and all the sudden my memory usage shoots up to 100% and my hard disk starts reading like crazy and I can't do anything on my system because its so slow. Like it takes a few minutes just to open a menu and trying to open a terminal or system monitor is pointless. Even pressing Ctrl + Alt + Backspace takes like 5 minutes to get out of X. The only sollution is to hit the reset button on my computer or wait the 5 minutes to for Ctrl + Alt + Backspace.

How can I figure out what program is causing this? It's only happened a few times and so far I've found no pattern. Does this sound like a memory leak? Why doesn't the kernel have some kind of protection against this?

Open a console and run:

$ top

It will give a continuously updated readout of running processes and the % of system memory they use with the highest on the top of the list. That should help you identify the runaway process causing the problem.

Know that, unless your swap file is being destroyed (completely used) it is not a mem leak.

*nix systems manage mem much different than dos based.