If your computer won’t connect to the internet and you have exhausted all other solutions, check your computer’s IP. If it is of the type 169.254.x.x , there is a good change your Winsock registry keys have been corrupted. This sounds worst than it really is; It is actually very easy to resolve.
Home routers can sometimes be buggy and unstable devices. It is very common for a router to crash, specially in situations of high network / Internet traffic. A good example will be a trying to download a big file from the web while trying to watch a youtube video at the same time. You have to bear in mind that home routers are cheaply built and do not have the cooling capabilities professional routers have. Additionally, when you over-stress the router it might cause its internal CPU to overheat and crash. The solution for this is simple: reset it. Just unplug the router from the A/C, wait about 10 seconds and plug it back in and you should be good to go. If this keeps on happening on every download, it is time to get a new router.
An IP conflict is basically two or more devices on your network using the same IP address. Most of us at home use a DHCP type of configuration or what is called a dynamic IP, meaning the IP address on your computer is automatically assigned by the router on your home network when your computer is turned on. There are cases where a home user might prefer to use a static IP rather than a dynamic one, for example: having devices on the network that require port forwarding, like a game console. When using DHCP it is impossible for an IP conflict to occur, since IPs are assigned by the router. In contrast, a static IP is assigned by a person, and when humans are included into the equation, mistakes start to occur. So, if you are using static IPs on your network, make sure they are all different.
If you have dynamic IPs as described on the previous section, you can skip this. However, if you have static IPs in your network make sure you are using the correct IP for the Gateway. The Gateway is basically the last device on your network before going out to the web; this is usually the router. Make sure your gateway matches the IP of the router. Same goes for the IP address. The IP address must match the type used in your network. If your routers internal IP (gateway) it 192.168.1.1 your computer cannot have a 192.50.1.1, it won’t connect to the internet because it is on a different subnet.
Network cards do go bad from time to time, specially in areas where power service is unreliable . All electrical equipment is sensitive to changes in voltage and network cards are no exception. Surge protectors for network cards exist, however, they are not common and therefore not easy to find. Obviously there is no solution to this issue once it happens other than replacing the network card.
If your little brother, or computer-illiterate-but-adventurous family member has been playing around with your computer lately, there is a good chance that they changed the proxy settings under Internet Explorer, Firefox, Google Chrome or your favorite web browser. A proxy is basically a server on the web that channels all Internet traffic though it. They are mostly used to bypass website blocks imposed by the network administrators. Companies usually block access to sites like Facebook, Youtube, etc. Proxies act as tunnels that let employees escape these blocks. The use of proxies not only applies to the work environment. If you have kids in your house and you are using software that blocks content not suitalbe for children, there is a good chance that your kids have been messing with the proxy settings to bypass your blocks. If proxy settings have changed, your computer won’t be able to connect to the internet. Proxys are designed to redirect all Internet traffic through a single IP and if that IP entered wrong in the settings, or is non-existent while the proxy setting is enabled, then you are going nowhere fast.
I can’t really remember when was the last time this occurred to me; fortunately my Internet provider is very reliable. However, since it happens to be a rare occurrence, (at least in my case) it could take some time to figure out even though in reality finding the cause is a simple and trivial matter. Check your modem’s lights: one of them should say “WAN” or “Internet” or have a little world globe sign; if its light is off or it is red, your modem is not connecting to your Internet provider. To make sure it is not the internet provider’s fault, unplug it from the wall, wait 10 seconds and plug it back in. If the Internet light does not come on in a few minutes, call your provider.
I have left this one for last, since it does not take a rocket scientists to figure out you are infected with spyware.
Hoped I helped!
