Webcam & Dimension 4500 problems

Just purchased a Compaq USB Webcam (cpq64cam) for my Dimension 4500 but am unable to get it installed.  "Setup Wizard has not detected any video devices" is the error message.  I've reloaded the software & replugged the webcam into different USB ports but no luck.  The Webcam's web site ( www.microinv.com/compaq) didn't provide much help.   I wonder if it could be a conflict with my tv tuner board.  Device Manager shows PC Camera (6025 VGA) with the yellow exclamation point under Imaging devices.  Any suggestions on how to get it working?  Thank you for any help you can provide.

DFW

 

Dimension 4500 2.4ghz P4

512mb

80gb HDD

NEC NR-7900A CD-ROM drive

Samsung DVD-ROM SD-616T

Iomega Zip 250 USB drive

Nvidia GeForce4 MX 420

Creative SBLive

Hauppauge Win/TV 878/9 tv board