Hi annangers and welcome.
If you want to share movies, music and photos across a wireless network, you need to install Server software on your PC. Have a look at the Sony Homestream free software available here: -
If you want to see the computers desktop, you will need to connect with a VGA cable.
I also want to connect my pc to my kdl 46ex653(.with built in wifi) to my computer as I watch bbc iplayer. I bought this model as I thought I would be able to connect without cables. I already have an older set but this is only wifi ready so I connnect to my pc via hdmi cable.. Have I wasted my money?