Well ok i just got a brand new Toshibia HDTV, so i went on the web and look for cables to hook up, my HP pavilion 774e, to my TV so i went and bought a HDTV RGB/ 15pin to 3 RCA Component Video cable, as pictured here i hook it all up right. blue, green to green and red to red, put my tv to HDTV colorstream 1 wich is were i put the component cord, it turns on the tv does a quicke flash of the blue HP screen, then nothing happens it just sits there black.
Check the settings on your computer. You'll have to turn the external monitor on usually with shortcut keys like fn+5.