1, too far, no signal.
2. The wireless switch is not turned on. Notebooks generally have wireless network hardware switches (such as Fn key and a combination key or physical switch), and each notebook has different keys. Look at the icon carefully, it is generally easy to identify. Generally, notebooks are Fn+F5 wireless.
There is something wrong with the driver. There may be something wrong with the driver of the wireless network card, resulting in no signal. At this point, you should reinstall the driver. If you are afraid of trouble, you can use the driver wizard to drive your life or install it like a fool.
4. System service problems. This is the most easily overlooked, and most of the problems of not finding wifi signals are basically here. Open Administrative Tools-Services. I remember it was wireless zero configuration (WZC) under XP, but Windows 7 didn't have this service, and WLAN AutoConfig(Wlansvc) was related to wireless connection. We should ensure that this service can be started normally.
5. In order to prevent surfing the Internet, some wireless wifi hides the ssid sign (the name of the wireless network), so it is impossible to search, so you need to manually enter the ssid number.