Can I run my win7 on another machine with different motherboard?
Solution 1:
Windows 7 will be aware that the hardware has changed and will ask you to call an automated 1-800 number to verify and re-activate your Windows installation and again on your return when you plug your HDD back into your current system.
Always remember
Microsoft can and will limit your number of activations, eventually making it more and more difficult to re-activate. I wouldn't recommend switching on a regular basis.