PC Problems Q&A thread

[Elite1]

Hey guys I bought a new HDTV and I want to use it as a monitor but im having problems. My new computer is able to do it fine(I plug in the cable into the white pc input using a converter) but my older pc which has a blue pc input does not display the picture on my tv. Is the older graphics card not compatible with my tv or is it someting else? I appreciate any help.