Had this one a few weeks ago, turned out too be the owners daughter had changed the 'Prooerties' settings for the 'Start' Panel to ensure the panel remained clear.
Solution: click Start > Right click the Blue header and click Properties.
Select 'Start Menu' tab this page allows you too change from the XP start menu option too the Classic Start menu option. Which ever you choose to run with click the 'Customize' box.
Under the Programs heading there is a box that can be altered to limit the number of programs that can be displayed, In this case it was set too Zero, default should be Six, altered same to suit owner,
Click OK, page closes, Click Apply then OK on Taskbar and Start Menu Properties page to close page and set new figures.
On the Customize start menu page you will find an advanced option were you can solve the documents dislay problem also.
Worked in this case, suggest you have a look.