Connected but pages don@t load on Pc ..fine on phone and tablet

[#1]

I've had a problem for a few weeks. my PC has a good conection but won't load pages......My tablet, phone and laptop all work fine. Today my neice visited and tried to connect to her phone and it wouldn't accept the router password ...This may be a clue as my other neice who was here also and had used my connection previously so didn't need the password logged in fine. I have reset the router still I can't load pages ...ideas anyone.

[#2]

Wifi passwords are case sensitive

[#3]

The password was entered correctly three of us checked ..and checked it was the correct case

[#4]

So can anyone access an external web site without using any mobile technology?

[#5]

Anyone who has used the connection before can connect because the password is remembered on their device but someone connecting for the first time the password is rejected.