Do you happen to mistakenly click the X which would close the Materials Palette on you? All you should have to do to get it back is go to...View>Palettes click on Material and it should come back. If you don't see it by doing that it means that you have inadvertantly dragged it off of your screen edge. I did that once long ago and what a pain!
As far as customizing your screen, do you mean customizing your tool bars and such in PSP? Like creating and saving your own personal workspace? If you go to File>Workspace>Save you can save as many different workspace as you like, just name them differently or you will overwrite and previous ones you had saved with the same name.
If you do a search in the PSP forum for Workspaces a thread should come up about how to do it!!
