The computer was working fine until I installed a new Lexmark print/scanner/copier machine. Now, the Logitech Web Cam connected to the computer will not work. Each time I try to use the camera, a message appears informing me that the camera is either unplugged or in use by another program. Upgrading and reinstalling the software does not fix the problem, nor does unplugging the Lexmark. Both devices run through a USB connection.

This is a surprisingly tough question! Let’s first rule out the USB port on the computer as the culprit. Try plugging the web cam into a different USB port which you know works (e.g., unplug the Lexmark and put the camera into that port). If you are using a USB hub, unplug the USB hub from the computer and plug the camera directly into that USB port. USB hubs are occasionally known to supply insufficient power to devices being powered off the USB port. If this fixes the problem, the USB hub should have come with a power cord to supply supplementary power to the hub. Ensure this is plugged into the hub.

Assuming the problem persists, it may be possible that the error message is actually telling the truth and another program is using the camera! This may have been a program which was installed by the Lexmark, or may just be a coincidence. Press CTRL-ALT-DEL and close all non-essential background applications. If problems persist, please contact me again.