If you downloaded the newest (Gutsy Gibbon 7.10) then Compiz Fusion will be enabled by default if your hardware can support it. System -> Preferences -> Appearance -> Visual Effects tab will show you the options for CF. Your laptop is insufficient to run it, unfortunately.
To install things you can use the incredibly easy to use "Add/Remove Programs" app, located under Applications -> Add/Remove. In the top left click "All supported applications" and select "All available applications" to broaden your search results. Search for something like "dvd ripper" or "video converter". Every program on there is free and clean. Just put a checkmark next to anything you want, and click Apply.
And you'll need this:
Code:
sudo apt-get install gstreamer0.10-plugins-bad gstreamer0.10-ffmpeg gstreamer0.10-fluendo-mp3 gstreamer0.10-plugins-ugly
type that in terminal (linux command prompt) (Applications -> Accessories -> Terminal). It will ask you for your administrator password (the password you use to log in) and then download audio and video codecs that are not included in Gutsy Gibbon.
edit: At the above command it may say that you do not have apt-get installed, just ender the command that it tells you is required.
Quick lesson on sudo:
Try the above command without sudo in front of it. It will not work on account that you need administrator privileges to modify essential parts of the system. By default you are a normal user, not root (superuser, can access anything, do anything). Any Linux aficionado will recommend you do NOT log into the root account normally (just log in as you do on the brown background screen). This is entirely a security and a guardrail because you can really mess up something if you are not absolutely sure what you are doing. Putting "sudo" before a command executes the command as an administrator. Kind of like UAC in Vista (but without the suck
).