Unblocking executable files on Vista
Sometimes when you download an executable file to your Vista computer and then try to open (execute) the file, an Open File – Security Warning dialog box will appear saying "The publisher could not be verified—are you sure you want to run this software?" If you know that the file is safe to open (run) you can prevent this dialog from appearing in the future by doing the following:
1. Right-click on the file in Windows Explorer and select Properites.
2. Select the General tab of the file's properties sheet.
3. Click the Unblock button and then click OK.
If you want to disable this feature entirely, you can do it using Group Policy by going to User Configuration \ Administrative Templates \ Windows Components \ Attachment Manager and enabling the policy named "Do not preserve zone information in file attachments".