Hi, reset your router MTU 1430 then with Dr TCP reset your PC Windows MTU 1430 make sure you save the settings and reboot PC and router.
You download Dr TCP from this website
http://www.dslreports.com/drtcp
And when you have the time, carry out this procedure to find the specific MTU for your connection.
I prefer to find the MTU this way,
Finding the largest MTU by EXPERIMENT version 2
First reset windows with Dr TCP to MTU 1500.
Then reset modem/router to MTU 1500 save it, reboot PC and modem/router.
Next from windows, go to Start/Run and type in, cmd (click OK)
At the MSDOS-PROMPT type,
ping -f -l 1472
www.bbc.co.uk
Then reduce 1472 by 10 until you no longer get the "packet needs to be fragmented" error message or