Any suggestions on how to track down a corrupt font?

I have the 2006 os installed, and somewhere along the way, I lost the apostrophe in the font used to display the rss feed summary on the top level screen. Instead of an apostrophe, I get a small square box with four numbers, one in each corner, 0 0 across the top and 9 2 along the bottom. I have not noticed this anywhere but in that top level rss summary box.

Any ideas where this came from [or how to fix it] would be appreciated.

Thanks, Clay