Few things you can try:
Disconnect your router/modem for 5 minutes (remove the power as well as the telephone line cable) and connect them up again.
Also worth checking that you have the latest updates from Microsoft for Windows, and that you have the latest Adobe Flash running.
If this is happening across all browsers - I would suggest trying a different PC (with Windows 7 installed) at a family member who friends' house and see if the same occurs.
Lastly, you may want to try another username.
Let us know.
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