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I’ve been seeing a problem lately with a few computers. After installing the latest security updates, their WLAN card stops working. It is unable to acquire a dynamic IP address from any router, and setting a static IP address does not work either.
The cause of the problem is a Microsoft recommended hotfix, (815485). The hotfix is part of an optional, though recommended update to Windows XP.
Resolving this problem can be done in one out of two ways, either by uninstalling the specific hotfix, or by rolling back to a previous system restore point.
Uninstalling the hotfix:
- Go to the Control Panel and open the entry “Add or remove programs”
- Scroll to the bottom and look out for an entry called Windows XP Hotfix (SP2)Q815485
- Remove the entry
The other solution hinges on System Restore being active on your computer. If it is, simply follow the instructions (given here) from Microsoft to roll back to a restore point from before the problem occurred.