|Two easy checks you might to want to make to start with:|
Open Internet Explorer
Go to the 'File' drop-down menu.
Make sure that "Work Offline" is NOT ticked.
If it is, click it to remove tick.
Now, go to 'Tools' --> Internet Options
Click the 'Connections' tab
Click the 'LAN Settings' button.
All three tick-boxes should be UNTICKED in LAN Settings dialog.
Restart Internet Explorer.