Did you notice that you are unable to access quite a few webpages? Even Google’s gmail service produces this annoying error message on your browser?

Did you try to install Windows 7 64 bit on your mac and instead of booting up normally, you received a message like the following on your screen?

1.
2.
Select CD-ROM Boot Type : _

If the answer is yes, here you can find a step by step solution to your problem. (Note: To follow this procedure, you must have a PC running Windows as the Operating System):

Have you ever tried to install Windows 7/Vista x64 on your intel based mac? If you have done so, you already know that the process of installing and running Windows 64bit is absolutely fine, even without the original drivers from Apple. Normally, in order for the hardware to work smoothly and as expected, you have to install boot camp v3.0 drivers from your Snow Leopard (10.6) dvd.

According to Apple, only a few intel based models are capable of running 64bit Windows which is not true. The list of apple computers capable of running 64bit Windows, which is originally published by apple is the following (http://support.apple.com/kb/HT1846):

I was playing with a partition manager application in order to create a new partition on my single hard drive. After restarting my PC, Windows 7 couldn't boot. The error message "Operating System not found" was shown and the only thing I could do was to shut down the PC. After a few searches on the web I discovered that the reason for this problem might be a faulty hard drive. But in my case, I was sure that the hard drive was not faulty because firstly, my PC was only 2 weeks old and secondly, I was previously playing with a partition manager application which might cause inconsistencies to the hard drive.

Hence we conclude that the problem might be a broken Master Boot Record (MBR). Here are the steps followed to fix this problem: