Canon A95 Works on Laptop but not PC

My wife has a laptop and I have a PC both running the same version of Vista.

When we plug her Canon A95 digital camera into her laptop, the autoplay
brings up the appropriate app, and she is able to download her pics and
movies.

On my PC, the first time I plug the camera into a USB port, Vista recognizes
a new device, loads the Canon driver, and says all is ok. In Control Panel
Scanners and Cameras, for a few seconds the camera shows up. After a few
seconds, it is gone. I cannot get the system to recognize the camera in the
same USB port again, but another port will go through the same process.
Autoplay never runs.

All other USB devices work perfectly in all USB ports on my PC.

I installed WMD 6.1 to see if that helped, but no joy. Next I will attempt
deleting all files associated with the Canon drivers and see if that helps.
Looking at the Canon website, there are no drivers to download. The site says
Vista already has the necessary driver...and yet, the first time Vista saw
the camera on my PC, it asked for the driver CD...hm.

Any ideas? Thanks!