Are you simply signing in using your registered email address and password?
Maybe your cookies are corrupted. Have you tried clearing them?
Make sure that your browser is set to default.
If you are running Internet Explorer 7 go to Tools/Internet Options/Advanced and click the Reset button. OK and exit, close and reopen IE7.
You will have to-enable all the browser add-ons.
If Internet Explorer 6 - go to Tools/Internet Options..
General tab: clear cookies, history and temporary files
Security tab: set all zones to default
Content tab: disable
Advanced tab: set to default. OK and exit.
Scan you machine for malware using the free version of this tool: http://www.superantispyware.com/supe...freevspro.html
The only other thing that I can suggest is to use the Chat link to speak to Customer Service. It is linked in my signature.