Vista - Autorun dropdown options went missing

Hi,
I face a weird issue with my Vista Enterprise edition. Sometime back suddenly one day all the autorun settings disappeared from my system.
When I checked the autorun defaults setting from the control panel I see that that dropdowns have gone blank completely. All the default options like "Open folder..", "Take no action", "Ask me everytime", etc. are simply wiped off... No more there!
Later when I installed some software like picasa, winamp, etc. these programs got added to the options list in the autorun defaults, but the above default options are still missing.

Now the autorun works in my system, and automatically launches the applications like picasa or winamp for appropriate disks, but I can't set/select the options like "Take no action" or "Ask me everytime" anymore

Can someone please tell me how I can add those default options back again?

Thanks in Advance.