I also posted this on the official xbox forums but they're really slow, and you guys seem knowledgeable about these things, so I'll give it a whirl here and see if I can get any help.
copypasta'd from my xbox thread
I am having issues connecting my Xbox 360 to my laptop. The cables are all inserted correctly in both the Xbox and my laptop, however when I switch display modes, it either instantly switches back to my computer's display or turns all black.
I do not know what the problem is, I've used the online troubleshooter and it did not help at all. I'm using a Komodo gold-plated HD VGA cable connected to my laptop, which is an HP running Windows XP SP3 with an ATI Mobility Radeon 9600 graphics card.
Any help is much appreciated.
I think the problem is with my laptop, or the cable is faulty..
I already tried google. Nothing.
THINGS I HAVE TRIED-resetting my xbox's display settings
-restarting my computer and xbox
-unplugging and plugging back in the cords (lol like that really does anything)
-attempted to use a different laptop (it's equally stuffty but hey it was worth a shot)
..does this go in Games? this isn't really talking about a game and there isn't "miscellaneous help" or anything lol