You've not told us whether you're using an Ethernet cable to connect to your router or wifi. (Indeed, you've not even told us whether you're using a Windows PC or something like an Android tablet or an iPad).
However I'll assume that you're trying to use a Windows PC with a wifi connection. In that case, the first thing to try is resetting the TCP/IP stack. Scroll down to 'Let me fix it myself', here, and follow the instructions:
https://support.microsoft.com/en-gb/kb/299357