Sync problems

Hello everyone

i am a holder of an iPhone 6 and I recently changed my windows laptop to a new one. Since I installed the latest version of iTunes, I face the same problem each time I connect my iPhone: there is neither automatic synchronization at all, nor automatic back up of the iPhone contents on the computer (despite the initial choice of automatically back-up which is clearly clicked at the iTunes menu). There is, of course, no sync between the iTunes library and the device. Moreover, I encounter huge problem of assessing my iPhone's contents (photos). There is a possibility of 1 in 10 efforts concerning the assess to my iPhone photos. I have installed of course the most recent iTunes and iOs versions.

Moreover, when I try to retrieve a backup, there is a message about deactivating Find iPhone from my iCloud settings (??)

please help.

thanks in advance

Nestor