Connect my onkyo to pc

wireless video and audio?

if you have sandy bridge you can get a wi-di box and use hdmi input on the onkyo assuming it has one.

if not you can get a usb dongle that wirelessly transmits to hdmi.

if not you are out of luck, need a lot more information about what you are trying to do

Easiest way, get a Y-cable connect the headphone jack to back of PC where audio goes out then connect the red and white RCA adapters to one of your channels going 'In" to your reciver. I assume you want to connect your sound system?

The wireless range for video/audio is not so great so I hope your PC is close to your PC. There are a few options. As mentioned above you can go with Intel if your system is compatible:

http://www.intel.com/content/www/us/en/architecture-and...

Or there is something like this:

http://www.engadget.com/2011/10/28/warpias-streamhd-val...

There are a few different implementations of wireless HDMI. The above are only two but you get the picture. Use the power of the google and searcxh for "Wireless HDMI".

I've tests where its worked from the next room, through a wall with no degradation.