Can anyone advise how to connect a laptop to a Xbox 360 but not using a HDMI cable? I know you can do the Media Centre thing but I essentially want to use the 360 as a second screen.

ETA: My laptop runs on Windows 8.

It's not exactly clear what you are trying to do. What do you mean by using the xbox as a second screen? The xbox doesn't have a screen so I'm struggling to think why you would connect to it rather than whatever display device you have the xbox hooked up to.

Connecting directly to the display device is surely going to be a load easier than trying to go via the xbox. Even assuming it can be done in the first place, which I have my doubts over.

Using the Xbox connected to the TV as a second screen. Instead of using a HMDI cable to do it

Do you mean using the TV as a second monitor that you can display anything that could also be displayed on the laptop's own screen? For example running a word processor or some other program?

I have my doubts there is any way to do that using the xbox as an intermediary. I presume also you were hoping to do so without any cables between laptop and xbox otherwise I cant see why you don't want to use a HDMI lead into the back of the telly.