Wi-fi on iMac not working, but works on other laptops

Question

Hi there,
I've recently moved back home with my new iMac, and when I went to try to set up wi-fi on it for the first time, it didn't work. I received a message that "Wi-fi has the self-assigned IP address ____ and will not be able to connect to the internet.". I don't understand why it's not working when I'm currently typing this from my macbook pro which connects perfectly fine, as well as my iPhone, and my parents laptops as well. The wi-fi worked perfectly fine at my old placres
I've tried resetting my modem and router, restarting my computer, turning wi-fi on and off, deleting the keychain access for the network, and tons of other suggested solutions but to no avail. I also just tried manually imputting my IP and that told me it connected, but the network icon still showed an exclamation mark, and I wasn't able to load any websites.
Needless to say, I'm extremely frustrated about this, and nothing seems to work. Are there any other solutions I can try? I really don't know what would be causing this.

Answer 1

When you see an exclamation point in the Wi-Fi menu, from the menu bar, select
 ▹ System Preferences... ▹ Network
Click the Assist me button and select Assistant. Follow the prompts. You may get a warning that Wi-Fi is not available, that you're too far from the base station, or that you're using the wrong password.
Assuming that you've ruled out those possibilities, click the lock icon in the lower left corner of the preference pane and authenticate, if necessary. From the Location menu at the top of the window, select Edit Locations. A sheet will drop down. Click the plus-sign button to create a new location. Give it any name you want. In the new location, set up the Wi-Fi service with the same settings you used before. Click Apply and test.