Xbox turns on but my controllers won't connect to it and tv?

Have you tried re-syncing the controller to the console? http://support.xbox.com/en-AU/xbox-360/accessories/connecting-game-controllers

Alright the best thing to do in this sitiation would be to re-sync your controllers to your Xbox Slim. If you have a Play And Charge cord use that then it will be much easier an should reconize it. I have had the same problem before, sometimes the wireless controllers interfere with other wireless items in the room. Hope this helps you out!

i tried that still wont sync

:/

Try using a wired controller if possible just to check whether it's the Xbox itself

Secondly just try holding the re-sync button on the console at the same time whilst holding the controller re-sync button to see if that fixes the issue sometimes they need to be both held until the controller connects

if you are using hdmi then the controllers will not connect until the tv gets the hd signal from the xbox. my controllers will keep blinking until the tv finds the signal, so the main issue is the lack of signal to the tv, is your hdmi cable plugged in properly? mine comes loose from time to time. id the cable faulty? have you maybe plugged it in to the wrong hdmi channel if you have more than one on your tv? I have 3 hd ports on mine and i have often plugged it into port 1 and then try getting signal from port 3.

Use the AV connection then switch back to HDMI.