You can't. HDMI is digital. RCA is analog (component or composite).
It would depend on what kind of outputs your laptop has and what kind of inputs your Television has. If you have a HDMI output on your computer, but only RCA inputs on your television you'd have to find a converter from HDMI to RCA.
Both the source and the TV have to have a HDMI connector. If they don't, use the S-connector. No S- connector? you will have to use the VIDEO connection on the TV.
Try to connect yellow into the green input while using red and white to the matching inputs. If this does not work, you may need a converter box sold about anywhere online RCA to digital/HDMi converter.
You will need an RCA to HDMI converter to connect the Nintendo 64 to a new TV, as most modern TVs do not have the older RCA inputs. Simply connect the yellow, red, and white cables from the Nintendo 64 to the converter, and then connect the HDMI output from the converter to the HDMI input on your TV.
all TVs connect the same by matching the 3 RCA color coded plugs into the TVs inputs unless you purchase optional PS3 component connection cables or HDMI cables
If your surround receiver has 2 HDMI inputs, connect both the PS3 and the Xbox 360 to the receiver with HDMI cables, and then connect the HDMI output of the receiver to the television. Simply connect the PS3 and Xbox 360 to the A/V inputs whether they are HDMI, Component, S video, RCA A/V, ETC. It does not matter if it is 480i 720 or 1080P as long as it is a Projector TV and not just a projector
The Bose 321 system does not support Hi-Def inputs, so the best idea is to use it just for sound. Connect the digital audio output of the Cable box to the optical input of the 321. Connect an HDMI cable from the Cable box to the TV directly.
Pico projectors are great. Like most of the elecrontics today that have to carry a video signal the most common inputs are A/V (RCA), VGA (laptop), and now HDMI.
If you TV has output connection, then you can get cables to connect your TV to your projector. For example I have a TV with RCA video and audio outputs, I use 3 RCA cables and then I connect them to my RCA inputs into my projector. My projector has a small speaker, so most of the time I just connect the video cable.
If you are using HDMI for display, connect also the RCA cables the PS3 comes with, and connect to them the x12 rca adapter. Then go to settings and audio settings, and tell the Playstation to play sound through the RCA cables.
The TV set needs to have audio output connectors. If it has them connect the TV's outputs to RCA's inputs.
I'm assuming the headunit has 2 sets of RCA outs - Front and Rear. If so, then one of your amps will need to have RCA outputs(sometimes called pass through) as well as inputs. Run an RCA cable from the "rear" outputs on the deck, into the inputs of the amp that has outputs. Now run a cable from the outputs on that amp to the inputs on your sub-amp.