Problems with Blackboard, Facebook, Yahoo Messenger

Hello my fellow geeks,

I have been helping a friend via teamviewer on her laptop and I am not getting anywhere.

I did full virus, malware, spyware scan and its clean.
I did check the integrity of the computer system (on cmd: sfc /verifyonly) and no violations of the system were found.
She recently had the Microsoft virus warning (Fake AV), and a virus thru a USB flash drive.
But its clean now. I did the chkdsk utility, and it didn't find any bad sectors.

Only problem is when she access her blackboard, her classes doesn't show. When she access her Facebook, she's unable to post status updates or wall posts, when she gets on Yahoo Messenger, her Yahoo Messenger when she sends an instant message, it successfully send message to her friends but she cannot read the conversation she is having with due to the window turns white..

When she's uses her friend's laptop, she can view her classes on Blackboard, she can post status updates and post on friends' wall. And she can have a decent conversation on Yahoo! Messenger.

Here's the info.

Sys Info:

Windows 7 Home Premium Service Pack 1 (32 bit)
4GB of RAM
Intel Duo Core 2 CPU T6400 @ 2.00 2.00 GHz
Softwares:

Anti-Malware software:
Ad-Aware,
Malwarebyte's Anti-Malware

Security Scanner:
McAfee Security Scan Plus

Antivirus: McAfee SecurityCenter

Firewall: McAfee Security Center

Internet Browser: Firefox 3.6.16

I am not getting anywhere to solve the problem. If any of you geeks out there know the solution, I would appreciate it.

Thanks.