No can do as the receiver can't downconvert from HDMI to component. So you'd need both HDMI and component connections to the TV.
And you'll need to check whether your PC can output analogue component via DVI, or just digital, before that DVO-component cable will work, too.
As component doesn't carry any audio, your best bet, depending on the connections on your TV, is to do:
- HDMI for picture and optical digital for audio from Sky HD to receiver
- HDMI for picture and optical/electrical digital from DVD to receiver.
- DVI for video and either digital or analogue (depending on your soundcard's outputs) for audio from PC to receiver.
- Component and HDMI from receiver to TV.
Or, if your TV has at least two HDMIs and component video input, connect the Sky HD and DVD video direct to the TV via HDMI, and the computer video direct to the TV via component, with the audio connections as above.