Mobile Device Center recognition issue

Working with Vista Ultimate. HTC smartphone [Windows Mobile 6.1 installed]

had worked flawlessly for the first months of the year with regard to

recognition, email, and media. Not used for last two months due to travel.

Returned to find that the phone was not recognized as a phone but a removable

drive. Only change was an upgrade from Office 2003 to 2007. Now I do not

know if:

- Office 2007 was the proximate cause

- The two month hiatus

- OS issue

Do not know where to begin in troubleshooting this issue. Guidance sought