I have Win7 32bit IE8 and Firefox. This problem starts from few days. I am unable to browse secure sites ONLY if I am connected through corporate proxy address. If I connect from my home, no problem. With proxy enabled I can acces local intranet secure sites. Problem is only with internet sites. Tried the suggestions provided in the articles but no luck http://support.microsoft.com/kb/968089/en-us
Tried with a different user id..no luck.
Tried with alternate proxy server...no luck.
Restore to a previous point...no luck.