Regarding the question from Barnard...is this an HP all-in-one printer/scanner? Does it connect directly to the PC with a USB cable, or does he have it connected to his network with a CAT-5 patch cable?

If it's the former, a reinstallation of the software should do the trick. If it's the latter, I'd check firewall settings.

I have an HP3310 that is connected via my wireless LAN and when I installed Windows Live One Care, the firewall update completely blocked the ports that HP needs to make it work.

I went to HP's site and found the list of ports that should be accessible and plugged them into the firewall software. Worked like a charm.