A:Answer Hi traitaothom, We are sorry but we do not disclose the contrast ratio for this TV. However, the X750H features picture adjustment where you can adjust the color tone, contrast, brightness, and picture quality according to your preferences. You can check the link below for more information:
https://helpguide.sony.net/tv/gusltnr1/v1/en-us/07-02_02.html
You can show your computer display on a TV using an HDMI connection. Please check the link below for your reference:
https://www.sony.com/electronics/support/televisions-projectors-lcd-tvs-android-/kd-65x750h/articles/00231984
The X750H comes with a 1-year manufacturer's limited warranty. The turning on and off by itself of the TV is an isolated case. To improve the performance of the TV, we recommend that you always update the TV to the latest software version. For assistance on how to perform an update, refer to the How to perform a software update on your TV. https://www.sony.com/electronics/support/televisions-projectors-lcd-tvs-android-/kd-65x750h/downloads/00017095
Thank you for the inquiry. Jay