Thanks for your message and welcome. Sorry to hear of the difficulties you're experiencing with the power, but we'd be happy to help provide support. We will, however, need a little more detail from you. Does the media center lose power completely, or does it instead enter/exit standby mode? When the system does switch off, does it automatically power on once again, or do you need to intervene to do this?
I'd also love to know exactly what components you have connected in your home environment, and how exactly they're connected to your TV and audio-video sources. Additionally, does your remote control these third-party systems too?
As a starting point, our support site has an article HERE that I'd love for you to take a look at. Please do let us know exactly what steps you attempt within the article, and the outcome of these steps. While there could be a physical fault with the system, it could be a simple setting, such as the sleep or CEC settings on the system as noted on our support site. Have you recently connected a new device to the Lifestyle or you TV?
Feel more. Do more. Be more. Come check out my profile here. New to the community? Check out the Getting Started board. Help others find answers to your questions by clicking on 'Accept as Solution' at the bottom of a reply. If you see a post you like, make sure to give it a thumbs up!