To view and modify windows32(bit) files such as dlls, exe, ocx and more you
need a hex/binary editor or you can try these:
resource hacker:
http://www.angusj.com/resourcehacker/
Resedit
http://www.tgtsoft.com/prod_rb.php
Resedit can be useful in editing alpha channel bitmaps that would just
appear 'black' in reshacker.
Reshacker is more useful for text and binary editing (if you wanted to
change your 'start' button text to "your name"). With this app you can just
drag and drop files into it to view their contents.
What files you are looking for depends on what you want to change.
I reccommend doing a google or 'c:\'windows\ search for:
uxtheme.dll, .msstyles, .theme, shell modification, themes, ........
and look for how to's and what its all about.
'c:\' refers to your OS drive letter.