Hi everyone:
O.K., I solved this problem and got my SoundBlaster Extigy to work with Win 7 (64-bit machine). Here is what to do:
[FONT=&] Easy part: [/FONT][FONT=&]
 1. Search your system for the old USBAUDIO.sys driver:
   C:\Windows\System32\DriverStore\FileRepository\wdma_usb.inf_9ce240de 
 2. Copy old USBAUDIO.sys, (d.02-11-2006) to usb or floppy [/FONT]
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Trickypart : [/FONT][FONT=&]
 3. Go to C:\Windows\System32\Drivers 
    Rightclick USBAUDIO.sys (d.19-04-2008)> Unlocker >Choose Delete
 4. Copy old USBAUDIO.sys, (d.02-11-2006) from usb or floppy  toC:\Windows\Systems\Drivers
 5. Reboot.[/FONT]
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6. At reboot, Windows will block the Extigy from starting "because the manufacturer’s software was known to cause problems." Go into Device...