|Start > Run > type cmd >OK|
Command prompt will be open.
Type cd\ and press enter
type ipconfig /all and press enter
write down ip address of computer and ip address of DNS server.
type ping ip address of DNS.
If request time error come that means there is the problem with connectivity.
If replay from ip comes that means there is no problem with connectivity.
You should try open internet explorer. If you are not able to open then you can optimize internet explorer.
you should delete all temporary files, temporary internet files, cookies, history, SSL.
Open internet explorer >Tools > internet option>
In general, delete all cookies, files, clear history.
In security, set as default.
In content, clear SSL.
In advanced, Restore default.
You can also scan your computer with spyware removal tools and updated anti virus program.