Who is your ISP, AOL?
I can tell you how to change the MTU value if you want to try that. click here and download DrTCP. When you've downloaded the program open it and look for the part "Adapter settings, MTU". Put the new value 1400 in the box to the right and make sure your network adapter is selected in the drop down box. Remeber the old value in case you need to revert, then click on Save and reboot your PC.