How to conect a pc to a panasonic plasma th50px75u?

Panasonic didn't make it a simple matter to connect a computer to this TV since they didn't include a VGA input connector. You can still do it, but it will require some adapters or changes to your PC.

If you're using a laptop, you have two options. If the laptop offers an s-video output, you can use a suitable cable from there to one of the set's s-video inputs. If there's no s-video output, the other option is to purchase a VGA-to-component breakout cable, available at a number of online vendors (search with Google). This cable has the VGA connector to the computer on one end, and 3 RCA plugs at the other end. You would use this cable into one of the set's component video inputs.

With a desktop PC, you can still use one of those two options. In addition, there may be a DVI video output connector available as well. This is not common on computers with integrated video, but is frequently found on many newer expansion video cards. If your computer has this connector (or you install a new video card with one), you can use a DVI-to-HDMI adapter and connect an HDMI cable to one of the set's HDMI inputs. Many video cards with DVI outputs include one of these adapters already.

So while it's not going to be simple, it's certainly possible to connect your PC to this TV.