I cannot get the home sharing to work. Network ok. Turn on and reset each device separately and simultaneously and up to date iOS? Please help

I have tried everything to no avail but I cannot get Home Sharing to recognise my ipad or iphone or home PC in the computers section. I have home sharing turned on. I have reset everything and rebooted too. All software is up to date. What may be causing this? I can watch you tube or get radio stations and some photos from the photo stream. When I double click the home button on ipad/iphone the sharing option does not come up either