Had to roll back a Microsoft update on Karen's laptop today. It screwed up the TCP/IP stack in an odd fashion: ping and nslookup worked fine, but neither Firefox nor Internet Explorer could actually contact any external Web sites, either by name or by IP address. Nor was her email client able to contact the server. She had no problem communicating with the LAN (she could reach my development Web server with no trouble at all). And it all worked fine before she installed the update.
"Always trust content from Microsoft", my ass.
The Ethernet circuitry on one of my motherboards got weird recently; it was purportedly a gigabit port, but data went through it like frozen molasses through a coffee filter. A test file, which took under two seconds to transfer on another machine with a working gigabit connection, got about a quarter of the way in fifteen minutes on the bad machine before I killed it. I had a spare 10/100 card to throw in there temporarily, and went online to look for a gigabit card. Best Buy price: $30. Newegg price: $7.49. ("Best buy", my ass.) So I bought four of them, since I have a couple other machines that are crawling along at 100 Mbps, and it would be nice to have one as a spare.