There might be a problem with your DNS servers of the ISP. A computer by default uses the ISP's DNS servers. You can manually configure your DNS servers. It is free and usually better than your ISP.
- Go to Control Panel ? Network and Internet ? Network and Sharing Centre
- Click on Change Adapter settings.
- Right click on your connection icon (Wireless Network Connection or Local Area Connection) and select properties.
- Select Internet protocol version 4.
- Click on "Use the following DNS
server address" and type either of the two DNS given below.
Google Public DNS
Preferred DNS server : 8.8.8.8
Alternate DNS server : 8.8.4.4
OpenDNS
Preferred DNS server : 208.67.222.222
Alternate DNS server : 208.67.220.220