how to complete tnansaction

Run the iTunes diagnostic to troubleshoot the problem. If iTunes encounters an error it should provide a link to troubleshoot any problems, if not you may be prompted to contact technical support so you will need the information from the diagnostic for the tech.

Note: iTunes Diagnostics is used to gather and display information about your computer—it does not resolve issues itself. You can use the information provided in the diagnostics to troubleshoot an issue you may be having, but you may need to follow specific steps in a related article or have assistance from an Apple Advisor to resolve an issue.

To run iTunes Diagnostics:

1. Install the latest version of iTunes.
2. Open iTunes and choose Help > Run Diagnostics.
3. Select one or all of the tests and click Next.
   To learn more about each specific test, select one of the appropriate links below:
   
   • Network connectivity tests
   • CD/DVD drive tests
   • Device connectivity tests
   • Device sync tests
4. Run through each of the selected tests. As you complete each test, you may see links to various support articles to help you resolve any issues you may be experiencing.

Here is the link for the info above:

http://support.apple.com/kb/HT4216