The first suspect was the installed antivirus program. I compared the settings because for all my machines I use the same antivirus program, but there was no clue at all. All my machines use Windows Platform (Windows XP SP3 and Windows 7 Ultimate).
After searching in Google, I have found posts on some forums mentioning about hosts-file in Windows which is used to translate human-friendly address into IP address. Usually we use hosts-file to create loopback addresses so that several requests to some addresses will be redirected automatically into our computer.
In my hosts-file found in C:\Windows\system32\drivers\etc\ on my troubled notebook I see an entry look like this:
127.0.0.1 pagead2.googlesyndication.comThis is must be the cause of the problem. So after I delete that line....VOILLA!!! I can see those adsenses again using any browser. Who has addes that line into that file remains unknown...but it doesn't matter right now as long I can view the adsenses.