Resetting the TCP/IP stack usually fixes such problems. (Don't worry, it's a lot easier than it sounds!)
Step 1 - Open an elevated command prompt:
If you're using Windows 7, click the Start button and type 'cmd' in the search box. Look for 'cmd' in the results panel above the box. Right-click on it and select 'Run as administrator'.
If you're using Windows 8 or 10, take the cursor to the bottom left corner and right-click to open the WinX menu. Select 'Command Prompt (Admin)'.
(In either case, if you're asked for permission for the program to make changes to your computer, grant it).
You'll now have a window with a black background open, with a flashing cursor in it. So you're ready for . . .
Step 2 - Reset the TCP/IP stack:
Type the following text into the box: netsh int ip reset resettcpip.txt
Hit 'Enter'
Restart your laptop
Step 3 - Cross fingers ;-)