strange AGP card

I have a Intel 740 AGP card,440LX motherboard.I have win 98 installed.Recenly I tried to install windows 2000.After the first restart & loading the drivers,when the screen “press enter to setup windows 2000 now” comes monitor goes blank.So i replaced AGP with SiS 6215 card & completed the setup.After the setup ,I again tried to use AGP,but after the white screen,monitor again goes blank.The same card is working on other 440 LX board on Windows 2000.The same card is working on same board in win 98,but it can’t work in windows 2000.I have put both the cards and checked if there is any conflict,but there is not any!