Opening a .pdf file in Adobe Reader

When I try to open an existing .pdf file from the Adobe Reader 10 Home Page, in the list of recent files, I get an error message as follows: 'There was an error opening this document. This file cannot be found'. This message occurs with most, but not all of my list of recent files.  I can also return to the original location (an E mail attachment) and open the file with no trouble.

This problem has existed on my computer for several months.  My Operating System is Windows 7.

Can someone help me with this?

Thanks,

Bernie Beal.