problem in opening facebook, gmail, twitter?HELP PLEASE??.?

[Anto]

I TRIED WITH MOZILA AND CHROME
IN CHROME:
Cannot connect to the real accounts.google.com

Something is currently interfering with your secure connection to accounts.google.com.

Try to reload this page in a few minutes or after switching to a new network. If you have recently connected to a new Wi-Fi network, finish logging in before reloading.

If you were to visit accounts.google.com right now, you might share private information with an attacker. To protect your privacy, Chrome will not load the page until it can establish a secure connection to the real accounts.google.com.
IN FIREFOX:
This Connection is Untrusted

You have asked Firefox to connect securely to twitter.com, but we can't confirm that your connection is secure.

Normally, when you try to connect securely, sites will present trusted identification to prove that you are going to the right place. However, this site's identity can't be verified.

[Sourabh]

Check your system's date & time if it is not the current time set it & then check the websites. If you seen your date & time changes when you switched your PC on then change CMOS battery in CPU.