ray, comcast HD cable box, surround sound speakers, and a Yamaha receiver. My system was hooked up,but I touched it trying to change my old DVD to blu ray and end up disconnecting more wire then I should have. Please help

The old dvd probably went straight to the projector.

If it didn’t, the dvd went to the Yamaha and then the Yamaha went to the projector.

If you can’t figure it out, connect the new blu ray to the projector, and if the projector has an audio out, run a/v cables back to the in on the Yamaha.

You can find diagrams online if you go to the manufacturers web site.