Chck with your network driver which is updated?
and stop your windows firewall.
which anti virus you r using? check is that blocking to your network?
Thanks Shri for your reply
But how to check whether my network driver updated?
If I used wireless, is it i also need check network driver too?
I am using either Avira Premium Security or Kaspersky anti-virus product.
Do you mean both anti-virus you r using? if yes you should keep one kaspersky is better one.
in network properties check wireless connection status and device manager\network adapter\wireless driver
Can you mention which M\C you have laptop or desktop with model? as per that you can check updated wireless driver on specific model.
And you can repair windows system with current OS. after first screen press continusly F8 some list will display,
in that choose repair your computer after that follow instructions.
Run netstat command from command prompt. Check out the number of your connections and the type...!. More than 150 connection (depents on the computer) make performance issues.