How to center finder?

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By Finder, do you mean the group of icons that are in multiple columns being forced to the right?

It is normal for all the icons to be flush to the right on the desktop if your View menu has an Arrange by selected. If it isn't arranged, then you can loosely manage the icons.

Do you mean the floating translucent bar with the icons known as the Dock?

If you mean the Dock, click on the Dock divider and change the location to the bottom or the left side. For more on controlling the Dock, see this article:

http://docs.info.apple.com/article.html?artnum=106850

If not, can you post a screen capture on a website and do an (without spaces before the I and before the >) in your post to show us what you are talking about? I.e. if I post from my Macmaps website the file called New.gif, I do which yields
when I remove the spaces from before the I and before the >.

On which Mac model is it? Is it happening on an external display or the built-in display?

Very odd sounding. I'll have to see a picture to know what to make of it.