When I start up my Xbox, it lands my on a page to connect cable to my Xbox.

Hmm It sounds like you have your xbox configured to start oneguide on startup. To fix this go to settings, power + startup, and then uncheck On start go to tv.

I am also having a similar problem. Whenever I try to connect my xbox to my router with an ethernet cable it finds my network but can not connect to the internet. Also when trying to set up a wired connection with my xbox it disconnects the laptops in my
house from the internet and these are set up wirelessly. I have a new xbox 360 slim and these problems have mainly started since the big dashboard update. Any thoughts would be appreciated.

Do you mean the first animated logo when you power up? try disconnecting the network cable. sometimes my xbox froze on that screen because it was busy trying to connect to Xbox Live. I disconnected it and it started up fine

My Xbox is too far away to connect via cable. I only recently started playing my Xbox again and I never had these problems when I was playing around a year ago.

see the thing isn't really the cable it is that the xbox doesn't seem to fully start up. it turns on, but it doesn't even kick on my kinect or connect to my controler?