Webcam under Skype no longer works - freezes PC

PC is Windows XP Pro. Webcam is Logitech Quickcam S7500. Skype is (now) V5.5.0.113.

I've been using this webcam with Skype irregularly for about three years. 2 or 3 months ago when I went to use it I found that when in Skype and with the webcam active the PC locks up. Only a power-switch-forced power down and boot would get the PC going. At that time I was using Skype V.4.1.0.179.

The webcam works fine with the Logitech control software and can see the picture, take snapshots, etc. Skype works fine voice only.

If I invoke the webcam in Skype, whether to set the video settings or in a call, within 5-10 seconds the PC locks up.

I've uninstalled and re-installed the webcam software, similarly with Skype. I've upgraded Skype to the latest version. All to no avail.

The webcam image seems to have developed a flickering most, but not all, of the time.

Could the webcam have failed and could such a fail have the affect of locking up the PC?

Any thoughts on the problem?

I've resolved the problem.

I tried the webcam on my netbook � disabled the onboard one. All worked fine on Skype. Put it back on the desktop � locked up after a few seconds on Skype

While it was actually working on the desktop and while using it via the Logitech software directly (no Skype) noticed the image flickering slightly which it hadn�t done on the netbook. Given both PCs are running XP with all the latest updates and generally the same software tried to think of differences. I wondered about the graphics drivers, tried to get into the Nvidia desktop control program, didn�t like it.

So I uninstalled and reinstalled the Nvidia drivers from the original CD.

Bingo! All working.

So clearly somehow and in some way the graphics drivers had got damaged or corrupted although I'd not seen anything else amiss to suggest such an situation.