I have several computers. Two of them say they can’t connect to the Internet when using Internet Explorer, but I can actually still browse. Other computers don’t do it.
By the way, I suggest you to use Firefox or Chrome for security and better privacy purposes. They are also featured.
May be those computers which are unable to connect to the internet may not be given access to do so. Give them access first. If your computers are networked, then i hoped then you can give access from the main computer. If not, then change the network settings of the computers that cannot connect to the internet.
Are your computers networked? What operating system do you have installed in them?
I am assuming that you mean that the other computers don't give you that message, not that they don't allow you to browse the internet.
A common cause of this is incorrect IP address settings. The ability to browse after receiving that message normally means that the gateway address is correct, but the browser is a bit confused due to the address on the machine seeing that the machine IP address and the gateway address are not on the same subnet. Communication is still possible because the wire doesn't care about the addresses and apparently your router can deal with the discrepancy. In most cases your router should be set up as a DHCP server for internal machines (unless you have another internal server for that purpose) and all of your machines should be set up as DHCP clients which will request all necessary address information from the server.
I have seen the same issue where all internal desktops work properly but the laptops complain because they were set up with static IP addresses that do not match the network configuration. If you go into the properties of the network adapter, select the IPv4 Protocol and click properties you will be able to change the addressing mode to DHCP (obtain address from server). The same setting should be set for your DNS server as well unless you are intentionally bypassing your ISP in order to use OpenDNS or another DNS service.
You can check your current settings by opening a command prompt and typing 'ipconfig /all'. This will display the configuration of ALL network adapters, including virtual ones. The IP address assigned to the adapter and the gateway should match the subnet mask usage. In other words, if the subnet mask is 255.255.255.0, then the first 3 sets of numbers for the gateway and the IP address should be identical and the last number should be different.