If somehow you have blocked some necessary programs from running or your anti virus did that you can try to do this for windows vista or windows 7
Start computer in safe mode.
logon on to administrator.
Click the start button
Select it and then “ctrl – shift – enter” to allow elevation request
Type in – “netsh winsock reset” press enter
Then Restart your computer
Another solution —
Boot in safe mode and login under a local administrator account.
Right click My Computer and click manage, up will pop up a computer management window, in that window double click Services and Applications and then click Services.
In the list of services scroll down to “System Event notification” and double click it. The properties for this Service will then display.
Make sure the start up type is set to Automatic and make sure the Service status is set to Started.
After you have done this click “Event Viewer” in the far top left of the screen and click “System”. This will bring up the logging of events in which have happened on your machine. This can help us determine what’s causing the error.
So click “Action” on the top toolbar and click “Save log files as,” save it somewhere and then upload it in your next post. Do not copy and paste it.
windows firewall reset-