[resolved] Windows fonts shrunk, menu boxes gone classic-style...

[Sharky.]

I previewed the XP silver "theme" (if you can call it that) yesterday, but now my Windows fonts are smaller than they used to be, and the drop-down menu boxes now look like this:

(and, when I make new IE windows, they don't open maximised)

How can I restore defaults?

edit: System Restore, thank you very much.