Macbook Pro 2003, Dynex dvi-d to hdmi, Mac wont detect display

So for a long time we let this mac sit in my house because the video display was screwed up, the black color turned red, that typical problem, but thats not what im worried about, i am having an issue with my mac not picking up the external display, I have a Sceptre 32" hdtv 1080 p, when i started working with this cable it didnt work after a good hour of trying to work with it, it finally worked on my tv, and for about a day i used it, i turned off my mac to sleep and the next day i try it and it wont come on, everytime i unplug and plug the hdmi into my tv it'll act as if its trying to connect that signal so its not my tv/hdmi side of the cable, but when i go to system preferances and hit detect display nothing happens, there is no arrangments tab, its as if my dvi-d port isnt reading that its plugged in or its reading as if there is no signal as well, im not sure if i should bring the cable back or test it with people at best buy, they will let me have a return up until january 13 so im fortunate 🙂 but id like this to work now, or at least not have the hassle of messing with them, ive searched around the internet ways to possibly have it work, none worked so far, any ideas? accepting any tips or tricks, and i will reply if they work or now 🙂 Thank You!!