I can't login to the App Store - connection failed...

yesterday I had totally forgot my password and security question & went through 'Apple Express Lane' in getting assistance to reset my password for my ID "[email protected]" account so I can update to Lion OSX & merge my MobileMe account to iCloud through the 'App Store'
the password was reset and was able to login to the App Store with new password and download OSX Lion.
I have now successfully installed OSX Lion and have completed all the updates up to OSX Lion 10.7.3
after the updates, I wanted to purchase some games through the App Store and tried to login, but I get a message in red
'Connection Failed'
I tried to find answers and post a topic in 'Apple Discussions Forum' using Safari 5.1.3, but it won't let me sign-in on my ID [email protected]' and my password.I get the following message :
'This Apple ID has been locked for security reasons. Visit iForgot to reset your account (https://iforgot.apple.com). Forgot your Apple ID?'
But I just reset it with the Express guy??
The other thing is I keep getting 'security certificates' popping up as well every time I attempt to login into 'Apple Discussions' or click to another webpage for a different site. Even when I click on legitimate(I hope) certificate to always trust, I find I have to repeat the step again
even with iTunes when I go to sign in I get the following:
iTunes can't verify the identity of the server "buy.itunes.apple.com"
The certificate for this server is invalid. You might be connecting to a server that is pretending to be "buy.itunes.apple.com" , which could put your confidential information at risk. Would like to connect to the server anyway?
so... wishing I didn't upgrade now
I had gone back to the apple support by email and they said I needed to reset my password again.
which have done and still no change. Twice now over the last two days in changing password.
When I use 'Firefox 10.0.2' I can login to iCloud & Apple Support Community & and don't get the pop up verify security cert's
I hope I have given 'enough' details, any help would greatly appreciated
My Hardware specs:
iMac 7,1
2.4Ghz Intel Core 2 Duo
4 GB Memory

I am having the same problem. It was working fine until yesterday.