Thanks for those screenshots.
Firslty could you uninstall the following program from add/remove programs:
Next open you device manager and 'uninstall' everything underneath the 'Universal Serial Bus Controllers' heading.
Once you have done that shut down your computer and remove all USB device from your PC (printers,scanners,webcams e.tc)
If you are using a USB mouse or keyboard then you can leave them connected.
Now boot into windows and your USB drivers should be reinstalled, open device manager and check to make sure that none are showing the yellow exclamation mark next to it.
Do you have the software CD that came with the webcam? - if so put the disk into the drive and install the software.
If it asked you to plug your webcam in then do so.
Once installed check device manager again and check for the yellow exclamation mark, if there is still nothing there then try to use your webcam.
Let us know if this helps or tell us where it fails.