I just upgraded to W10. I had numerous problems and thought I had them fixed after upgrading my graphics card to Radeon R7 250 1GB, but now I realize my iPhone will not sync its calendar with Outlook 2007 any longer. When I look in default apps I note that there is no default calendar selected. I tried to select Outlook 2007, but it doesn't give me that option. It tells me to look for an app in the store.

I don't know if the lack of a default calendar is the problem or not. Any help would be appreciated.

Dell desktop studio XPS 9000 with Intel Core I7-920 processor 2.67GHz and 8MB RAM.