As I understand it, the PX-5s USB implementation is "class-compliant," which means that it should work with a Windows 7 laptop without special drivers. What happens if you have another USB MIDI device connected? I have a FocusRite Scarlett 2i4 preamp with a USB connection connected to my Windows 7 dual-core laptop. Originally I also had an M-Audio Oxygen 61 connected, with perfect results. Now, I have the PX-5s connected instead of the Oxygen 61, and it doesn't seem to want to play nice with the FocusRite. Control Panel/Devices and Printers shows the PX-5s as an "unknown device," and its name does not show up in MIDI device listings in the Kontakt player. The only time the PX-5s seems to work properly with the laptop is if it is the only MIDI device plugged into USB. I have gotten around the problem by patching the PX-5s into the FocusRite preamp with MIDI cables, but I'd still like to know why I can't use a USB connection. Surely it's possible to use the PX-5s with a computer having a USB audio interface. Is it conflicting with the onboard MIDI on the FocusRite? Or perhaps it's jealous of the Oxygen 61 (which still occasionally shows up in the plugin MIDI list, even though it's not connected)? I have version 1.10 of the firmware.