Search:

Is it a click once application? You could try with isolated storage (ie: http://msdn.microsoft.com/en-us/library/3ak841sy(v=vs.100).aspx ) but that would make hidden to you too the exact location of...

add a manifest to your software where you stated admins right si required. This will bring out the "confirm you want the software do this", and in case user has not, it would ask for Admin pwd.
ie:...