bought a new mobo and cpu- reimaged hard drive, had this issue as well.. BH's guide worked for me..
wonder if this issue is related to ID buying the rights to ETQW from lac-O-vision..
the game is no longer on Steam as well..
read that's what happens when the rights change 'hands'.. all online sales and support for the game goes bye-bye until it's all get worked out or something..
Just glad, Q4 is finally on Steam, Bethesda bought the rights from activision a few months ago..
can finally add it to my collection.. lost my hard copy years ago..