Heres a LINK with some possibilites.
I know you said you have tried this,but heres a LINK
I also read that this could be a defective modem.
Tom
I have a notebook with Windows XP. After the computer has been switched off for several hours when I boot up and click on my broadand modem I get an error 797 which states that the modem is not found or busy. If I Restart the computer then the modem works fine. I have tried plugging the modem into my USB multi hub and then directly into the computer and reinstalled the drivers each time. I would appreciate any help.

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