samirss, you mentioned that accidentally posted a duplicate. So you asked how to delete it -- here are the instructions:
Next time you accidentally post a duplicate, click "Edit" on your first post at the top of the duplicate post, and then select the Delete checkbox. Then click Submit. That's how you can delete a whole thread.
(I have done this for you, so you don't need to do this now -- just next time)
Also, for what it is worth, I had a 7230 and when I plugged in my 7100t it did the same thing as you are describing. I had to uninstall the Desktop Manager and install the DM 3.6 SP3a software and everything worked fine...