For some reason my 4 USB powered hub ports quit working on my Dell 1905FP monitor. I have tried everything including plugging in the flow-thru cable into my other PC (where it is recognized "new hardware" and operates). When I plug in the flow-through USB cable on the inop PC it gives me the message "Unknown Device". But in the error screen when I click on driver details it says "No drivers are required or loaded for this device". I click it and try to upate drivers and when I get to Windows/System 32/Drivers folder, the "OK" button goes dim. This does not happen on the other PC and which is where I found the drivers should be used (folder and name). I look in the inop PC win explorer and the 2 drivers are in that folder. Both PCs are using Win XP Home SP 2 with all updates. Hardware is different, but it seems like the problem lies in the USB driver initialization. The Six USB ports on the inop PC work fine for everything except the powered hub on the Dell monitor. This used to work, but some other configuration change must have made this happen. I have a webcam on top of the monitor that has a very short USB cord so I really need the Dell monitor port to work.