Ok, I just googled the phillips freevents and it popped up with a pic of a laptop, but good to know it's a desktop. Using my incredible powers of deduction, I deduce that you are using windows XP or Vista. That leaves you with a couple options... either stick with the RAM you have... or get a 64-bit OS (Linux or Win 7).
Linux is free. I haven't used it with Maya, but it will give you at least a few headaches if you're not familiar with it.
Win 7 is not free. I have used it (x64 Premium) with Maya, and I'm very happy with it. No, your 32-bit apps will not necessarily be incompatible with Win 7 x64, most will likely work just fine. In addition, I'm fairly sure your Maya disc comes with a x64 version, and some of your other software may too (to take advantage of more system resources). I'm not recommending XP x64 or Vista x64, but only because I've heard negative things, haven't tried 'em.
As for going into the computer, you don't need to do anything you're not comfortable with, but it might be helpful to get familiar with the inside of the computer. Power down, turn off the switch in the back and unplug. Then unscrew the side and poke your nose in. You don't need to touch anything, just get a feel for what's all in there, and what RAM looks like for example. You could even give the floor and fans a quick gentle vacuum if it looks anything like mine usually does