i just got a unibody macbook pro (15" 2.53ghz core2 w/4gb of ram) on craigslist and didnt think to check the display port. the minidisplay port is loose and i can only get my external monitor working by playing with the connection until it starts working. i've used a mini displayport to vga adapter and a dvi adapter also and it acts the same way. computer isnt under applecare and the genius bar said itd be about $600 to replace it. this is very frustrating since i am web developer and really need that extra screen real estate. thanks!