[Solved] Plug the computer to a TV?

The answer to your question probably is provided by the HDTV. What you can do depends mostly on what that TV can accept as inputs, because computer video cards (especially one that is still being chosen) can have a wide variety of outputs.

At the lowest-quality video level you have a standard cable TV input (called Type F) and very likely a set of three RCA inputs labeled Composite Video and Stereo In (L and R). Next up is S-Video In, a round socket with several small holes for pins, and you need in addition the two stereo sound connections. It is very common to have component video (3 RCA connectors labeled Y, Pb and Pr) which accepts a combination of three separated video signals. This system, very common between a DVD player and the HDTV, also requires using two lines for the stereo audio signal.

The common HDTV video connection system now is HDMI, which combines high-quality video and audio signals into one cable and connector. An alternative is the DVI output on a computer video card which normally provides video only (but some exceptions), but not many HDTV's have an input for this system.

So check what your HDTV has for input connectors. If you have HDMI, plan to use it - it is high quality video plus audio. Then make sure the video card you purchase for your computer has HDMI output. While you're at it, check what audio properties your HDTV has. Many will accept and produce 2-channel stereo and not much more. Some, however, can at least pass a more complex audio signal system on, via a second HDMI cable, to a separate good sound system with multiple channels and perhaps digital audio input. Whatever your plans for audio, ensure that your computer can produce those signals, and that you know how to get them from computer to HDTV, quite possibly through the HDMI cable.

Many computer video cards have DVI outputs used for monitors. Now it happens that the video signals on these outputs are identical to the video signals on HDMI systems, so a simple adapter plug can convert from one output to another. HOWEVER, DVI outputs do not automatically have the audio signals in them. On computers, it is assumed you will hook up speakers separately to output jacks on the back panel. But SOME video card makers have ways to feed audio signals through the video card so they are available on the DVI connector for use by the converter adapter to feed an HDMI cable. If you plan to go this route (rather than having a true HDMI output in the first place), check the details of how audio is handled, and exactly which types of audio signal can be routed from where in the computer to where in your HDTV / audio system.