Fixing Network Issues
There could be many issues with your network, so they need careful examination. It usually takes 5 minutes to rectify commonly occurring problems (listed below) with Wireless Networks. Although mainly Wireless Network issues are discussed, but the same solutions will also help you to troubleshoot wire based networks issues.
Try to take out and re-insert the USB network device. Restart the router and in the meantime restart the machine. Most of the common issues will be resolved upon these restarts. Check if rests of the computers on network are working fine, as it may be the issue with ISP. Better try to reboot DSL or cable too.
Use command prompt for getting ‘iPv4 Address’ to confirm if there are no configuration issues with your router. Once in command prompt (go to it either from All Programs menu or directly typing cmd in Start menu search box) enter ipconfig /all. It will reveal a lot of information; see ‘IPv4 Address’ of the appropriate adapter here. For a home network, initial three numbers are same to DCHP server. Reset the router if the counterpart numbers do not appear same.
Windows Firewall may also be responsible for restricting network access. Turning it off may solve your problem too.
Try to connect your computer to the router directly with Ethernet cable. If the physical connection is working fine then you may have a malfunctioning wireless driver. Reinstall the driver and try, hopefully it will work. Driver could be retrieved from manufacturer’s website too.