Windows 7 Can Run Unactivated For 4 Months Page: 1
4 Months Without A Key
Windows 7 can be run for up to 120 days without entering a serial key, perfectly legal too! No need to continue running the RC until the 22nd of October, if you can manage to get hold of the RTM version you can use it for up to 120 days without entering a key. ComputerWorld has confirmed this with Microsoft, who say that the procedure is completely legal.

Microsoft confirmed that "-rearm" can be used as many as three times by Windows 7 users to avoid activation. "This means [that] a total of 120 days total time is available as a grace period to customers that take advantage of -rearm," said a company spokeswoman.
You can install Windows 7 without providing an activation key, you just have to click "next" when the installer asks you. From then on you have 30 days to activate before you are forced onto a reduced-functionality mode. However, you can reset the timer up to three times by simply opening a command prompt window, entering "slmgr -rearm" without the quotes, and restarting your computer.
Once the 120 days are up, you can enter a legit Windows 7 key and keep using the same installation. However, Windows Secrets notes that the RTM edition installs Windows 7 Ultimate by default, and entering a key for a cheaper edition won't allow you to activate. Check out the Windows Secrets article for detailed instructions on how to activate with a home premium or professional key.
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