Its taken me a little while to track this down, but I've found other reports on the web as well, especially related to the Asus A8N32-SLI motherboard that I have. If you install any software which uses SCSI Pass-Through Device (SPTD) drivers you may experience USB ports which just wont work at all. Software which uses these drivers is things like Alcohol 120% and Daemontools. The SPTD drivers somehow I am not completely sure block the proper initialisation of the Standard OpenHCD USB Host Controller almost consistently in Windows XP Pro x64. I believe Duplex Secure are aware of the problem though I don't know how a fix is progressing. At time of writing the latest public beta is 1.40 and this did not fix the issue for me. I've just removed Alcohol 120% and SPTD from my desktop and all my USB devices are working for it now. Hope this information helps someone else, the information is there already on the net albeit scattered across a range of locations.