Connecting to an open Wi-Fi network such as a free wireless hotspot exposes your computer to security risks. Although not normally enabled, most computers have a setting available allowing these connections to happen automatically without notifying you (the user). This setting should not be enabled except in temporary situations with your (the user's) awareness.
More Wireless / Networking Quick Tips
To verify whether automatic connections to open Wi-Fi networks are allowed, check the computer's wireless configuration settings. For example, on Windows XP computers having Wi-Fi connections managed by the operating system, the setting is called "Automatically connect to non-preferred networks." To check this setting, follow these steps:
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1. From the Start Menu, open Windows Control Panel
2. Inside Control Panel, click the "Network Connections" option if it exists, otherwise first click "Network and Internet Connections" and then click "Network Connections."
3. Right-click "Wireless Network Connection" and choose "Properties."
4. Click the "Wireless Networks" tab on the Properties page
5. Click the "Advanced" button in this tab
6. Find the "Automatically connect to non-preferred networks" setting. If checked, this setting is enabled, otherwise it is disabled.

