I continued to look for the file, but could not find it. I open norton utilities and deleted all the temp files in my computer. Although I could not find it, the offending file was deleted. Now, when I open reader, the pdf file still shows up in "open a recent file", but apon selecting it, adobe reader can't find it. this makes sense because I deleted the pdf file. However, I still have the file file displayed in the "open a recent file" area and I still can't get rid of it! I know I can delete readerX and reinstall it, but the next time I download a PDF file the same thing might happen again.
Don't download files you are afraid of showing up in your recent files or you can set the number of recent files to remember to be 1 and open a new pdf file. The Preference can be found in the Preferences->Document screen.