Mine has actually gone down a bit after they came and "fixed" the cable tv. I was at 117 down 16 up now I'm at 93 down 8.5 up but the cable tv works perfect now. LOL
If it is not the cable or hopefully the MB, then it could very well be a bad update corrupted something. I had a windows update make my onboard ethernet adapter stop working until I reinstalled windows for the 4th time and didn't do that particular windows update and it was working fine after that. the point is that not all updates are designed for your specific setup and will often have drivers and/or settings for different hardware that will mess up your setup. I would roll back to a earlier point before the most recent updates you did and noticed the issue and see if that works before suspecting the MB ethernet went belly up. Hope that helps troubleshoot some. If that doesn't fix it then I think your gonna be pissed. LOL
Nice responses so far everyone. I personally prefer my version of longhorn developers copy.(yes I was friends with one of the lead developers on Vista) It is rock solid and is before they put the developers bugs in it to force updates or upgrades