Indeed, in the first specification I find fro this cable modem, I read: "USB drivers for Windows 98SE, ME, 2000 and XP". So all you can do is ask the maker if they have USB drivers for Windows Vista and 7. Maybe it's on their website. Did you look already? If not, find their customer service or tech support.
Didn't you run Microsofts upgrade advisor? That might have warned you.
Kees
Hello I have a question. I have a scientific atlanta webstar dpc2100 modem. I just upgraded my PC from Winxp to Win 7. I have tried to install the drivers for the modem, but they don't work. I read the modem paperword and it says that it's compatible for winxp, win2000 and win2003. My question is, is there a way to may work with windows 7?

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