After investigation I found out that one of the access points close to his office was wrongly configured to detect rogue access points and flood them. The access point was in the middle of a long row of laboratories where the computers were all wired, and the user's office was at the end of the hallway. There were 10 access points per floor. Once in a while, his laptop would associate with the problematic antenna. The driver on his system was vulnerable to the packets sent, and it would make the computer crash. I updated the driver on his wireless card and the problem went away.
What I learned from this experience is twofold: First, sometimes a problem will never happen in front of you and everything will look all right on the computer. That doesn't mean the user is making it up.
Second, it's easy to blame things like Windows' stability or to label problems as quirks or unsolvable, but if you keep trying, you'll usually find the problem in the end. It sometimes depends on how much time you're willing to spend on an issue.
This story, "Blue screen of death strikes again -- and again and again," was originally published at InfoWorld.com. Read more crazy-but-true stories in the anonymous Off the Record blog at InfoWorld.com.