I had this same problem. you have to uninstall pro tools 6.4. Then go to http://archive.digidesign.com/download/audiodrivers/xp/ and download the audio driver at the bottom of the page. After you install the audio driver then reinstall pro tools 6.4 and it should run smooth.
I had this same problem!
I had this same problem. you have to uninstall pro tools 6.4. Then go to http://archive.digidesign.com/download/audiodrivers/xp/ and download the audio driver at the bottom of the page. After you install the audio driver then reinstall pro tools 6.4 and it should run smooth.