iTunes will not detect any devices?

Windows 8. 64 bit. iTunes 12.1.1

Something wrong with apple mobile device support - it's not listed under programs. I get iTunes message that software is not installed when I plug any device in. I've reinstalled 5 times, tried to use various fixes posted online to get mobile device to work, but so far no joy.

Any help much appreciated as at the moment I can't back up nor alter content on any of the household's devices!!!!!