I saw similar questions as mine, but wasn't able to find a solution. My Windows 7 laptop was just able to connect to wi-fi just fine the day before it stopped working. It displays signal with yellow triangle with an exclaimation mark. When I tried troubleshoot, it says "wireless network connection doesn't have a valid IP configuration". Other devices such as my sister's laptop that I'm using at the moment works perfectly fine connected to the same network. I've tried plugging off the modem and resetting it, tried some of the answers I found on internet, and even tried system restore, but all of them to no luck. Plus, I don't really remember making any significant changes before it stopped working. I will provide any additional information that you might need. I would appreciate your help!

I suggest you download the latest wireless driver from the computer manufacturer’s website and install it. If it does not help, temporary disable antivirus and firewall, then check the result again. If the issue persists, please let us know if there is a router in your network. If you have a router, please check the settings of the router to confirm if you have restrict the IP address boundary so your computer cannot get an IP address. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.