Thanks to everybody for your advice and suggestions!!! Some more info on the issue. It is win xp pro sp2 (2002 version). The mouse and the flash drive worked totally fine several days ago and as of now they work fine on another laptop. The problem is that they are not recognized by Windows when plugged in. When I plug in either of those devices into one of two available USB ports (USB Root Hub (2 ports)) I get the following message: "USB Device Not Recognized. One of the USB devices attached to this computer has malfunctioned and Windows does not recognize it." When I look at the unknown device in device manager it has a generic "libusbfl.sys" driver. I believe I should have all the needed drivers in "c:\windows\system32\drivers" but the system can not recognize the device. I have tried to copy the "msmouse.inf", "mouclass.sys", and "mouhid.sys" files to a separate folder and point to it when running the "hardware update wizard" but it didn't help. I am getting the message "the specified location does not contain information about your hardware" How do I install drivers for the unknown device? I have tried to "update driver" and going through the above "hardware update wizard". When pointed to the above folder (specific location) with the "msmouse.inf", "mouclass.sys", and "mouhid.sys" files I am getting the message that "cannot continue the hardware update wizard", "the wizard could not find a better match for your hardware than the software you currently have installed" USBDeview shows that both devices worked properly before but when I plug in the mouse and select "display devices without drivers" it shows it as an unknown device. So the question is how to make Windows recognize the mouse? I don't think I have a setup disk for the mouse as it is a basic microsoft optical wheel mouse... Will be grateful for your comments. Thanks