Changing the Registered Organisation in Vista

In Vista, click on start and type 'regedit' into the 'start search' textbox. Wait for the registry editor window to open. Click on 'Continue' if Windows needs your permission to proceed.
When the registry editor is open, proceed to: 'HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion' and change the 'RegisteredOrganisation' value to the organisation name of your choise.

(Click the image below to enlarge it. Some of the information on the image has been blocked)



If you need to change the registered organisation of all your applications, then, start searching (Ctrl-F) for 'RegisteredOrganization'. It may take a while for the registry to find all those values. When it does, change the value by double clicking on the 'RegisteredOrganisation' string and enter your Organisation name.

Press F3 to proceed to the next 'RegisteredOrganization' string and change it's value. Repeat till all the 'RegisteredOrganization' values have been changed.

Folks with a Classic Start menu can Go to Start -> Run ,
type in 'regedit' and wait for the registry editor screen to show up, and then follow the above steps

Edit: To see if your Organisation Name has changed, run 'winver.exe' by typing 'winver' into the 'start search' textbox.