Pimped,
Looks like to me that at 512MB of RAM, with a 2GB CPU, you have enough juice to run just about anything you need to without straining your system (except for serious 3D games released in the last year).
Just a quick question about your computer habits. There are few other users listed for your system. Do each one of you guys logout when you're done with a session, or does the next user just "switch" to their own account? I ask because there's a mechanism called Fast User Switching. It basically lets the other logged on accounts stay active in the background while you use your own.
You can probably see where I'm going with this. Those other logged on accounts use resources even if they're not in the foreground. Spyware, adware, unnecessary services, or programs running in the background, from your family's logged on accounts will reduce your system's overall resources, and therefore its performance. If you cleaned out your account, you may need to go and clean out everybody else's also.
You might also think about disabling Fast User Switching, or having everybody log out when they're done with the computer.
BTW, your D: drive is also getting close to full. You might want to clean it out also. At some point, you won't be able to defrag that drive (Defrag needs some room to work).