Unless you are doing 3D rendering or hi-end video editing, your CPU should almost never be running at 100% unless an application is taking hold of it (which it should not be doing). Check with Task Manager to see just which program is doing this and how frequently. Again, unless it is processing something, taking up a CPU at 100% is abnormal. I mean, doing 3D animation rendering would only take up to 50% or less… 100% is kind of crazy…
Again, to be able to run a lot of programs at the same time depends on the amount of RAM, not CPU. Perhaps you can get a board that allows 1.5GB or 2GB of RAM instead of the standard 1GB boards…