mikedurward
If you are familiar with using the registry navigate to...
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\ Policies\Explorer
Check there is nothing in the right hand window that mentions clock e.g. hideclock.
If there is delete it reboot and that should be you.
I would strongly recommend running Adaware or Spybot as spyware can cause this very problem.
FSD