When you press Start / Find, the Files or Folders and Computer commands may have disappeared.
If you right-click Network Neighborhood, Find Computer may be missing.
If you right-click My Computer, Find may be missing.
You have a corrupt or missing registry entry. Use Regedt32 to navigate to the following key:
NOTE: If the key path is not present, Add Key from the Edit menu.
There should be a <No Name> Value Name in the right hand pane that contains the following REG_SZ string data:
If the value name is not present, use Add Value on the Edit menu to add an un-named (blank) value. Then set the string data.
NOTE: The Find command can be missing from the Start menu if NoFind is implemented.