Computer won't connect to internet

Ok we have about 4 or 5 computers on our small network at home. Yesterday, the computer was running slow so i restarted it, when i did i was connected to the wireless but not the internet. When i ran network diagnostics, it was a firewall issue. I ran an antivirus and got rid of the issues. But now, it says i'm connected to the wireless but i cant get on the internet, when i run diagnostics it tells me to check the router, but the other computers on our small network can Does anyone know how i can fix this?

what is the brand and model number of the router and how many computer are there exactly and what operating system(s) are the computers running.

You can usually fix this by restarting your router, I come across this problem from time to time(not to often either) where I must restart the router to get a wireless connection.

hope it work, please let us know. thank you