USB Port Failure

I have a baffling problem which I could really do with some help on...

When trying to download a youtube video via the keepvid website - http://www.keepvid.com Chrome is crashing as soon as the Java Applet launches to retrieve the video download links. :confused:

However in addition to hanging, the USB ports on the PC all stop responding :eek: - taking down my internet connection at the same time as I'm using a wireless USB adapter. I then have to reboot the PC to get USB functionaity back !

I have no idea why this is suddenly happening as I was able to use this website quite happily a couple of weeks ago. If I revert back to using IE8 (which I really don't want to do) the website works fine

I'm running XP professional with service pack 3. Any help would be much appreciated...

Thanks

Steve