Westinghouse HDMI handshake errors

Hello, I have the Westinghouse 32 inch LCD TV Model# SK-32H540S.Purchased for $375 at walmart about 2-3 years ago. I have Comcast Cable hooked up to it I am using HDMI through my HD box and everything was working fine but now I have a PS3 and have that hooked up to the second HDMI port and it seems like when I shut off the PS3 the screen goes blank and then when I switch back to my ...