From Windows Control Panel, Add/Remove Programs, select the uninstall option, then select the 'Repair' option.
You appear to have a bad install.
If that doesn't fix it, then you may have to provide more information... like was it ever installed before? are you administrator on your computer etc etc
Erik
What version of ArcGIS Desktop is this?
thanks
Laurene Koman
The KB article referenced provides steps that do not require you to uninstall and reinstall ArcGIS Desktop - You might want to try those first.