I\'m trying to run a process as a different user that has Administrator privilege in 2 different computers running Vista and their UAC enabled but in one of them I get a Win
Try to replace
pInfo.WorkingDirectory = New System.IO.FileInfo(myFile).DirectoryName;
with
pInfo.WorkingDirectory = Path.GetDirectoryName(myFile);
The FileInfo makes an access to the filesystem, and I would assume only the admin user has access to that directory. If it doesn't solve your problem, at least it will make your code a tiny bit faster...