Take this as a warning kids, I'm a professional.
If your computer is running slowly, and you're using Firefox, Chrome, Safari or that other one, the problem is probably in your computer's fleshware*, and I have a bugfix for you. But first, the problem.
So sometimes I like to keep a lot of tabs open. And when I say sometimes, I mean always. And when I mean a lot, well:
I mean a lot.
And that does horrible things to your computer, especially when you are accidentally running all this:
You see that number under "Real Mem"? Notice how it says 2.15 GB? That means you are using $12,480 worth of memory (if this were the year 2000) JUST for your browser pig. (I should fork Firefox and rename it that. Browser Pig.) Having all those browsers and Illustrator open at the same time doesn't help. I'm actually proud and surprised that Photoshop wasn't on that list as well.
Anyway, I have a bugfix that will solve your problems:
* That's computer nerd speak for "user error," meaning it's actually *your* fault, not the computer's.