Excel deletes and resets Recent Documents
 

I am using Excel 2007 on Vista Ultimate on one machine and Vista Home Premium
x 64 on another. I have set the number of Recent Documents to 10 under
Options - Advanced - Display - Show this number of Recent Documents.
However, when I close Excel and then restart it, no recent documents appear
AND the number of recent documents under Options is now shown as zero (0).
I checked an earlier thread that suggested editing the registry at
HKEY_CURRENT_USER\Software\Microsoft\Windows\Curre ntVersion\Policies\Explorer\NoRecentDocsHistory, but this directory does not show up in my registry.
Any suggestions? Thanks in advance!