Originally Posted by vernong1992
On an OEM version you would, because its supposed to work for one install only, then it'll nag you when you activate Windows that its already been activated
This is only true if the install was done on a PC with different hardware than was first Activated with.
If you reinstall Windows on a machine that you have previously installed and activated Windows on then you will not be asked to call M$.
There is a small hardware profile which is saved and sent to Microsoft when you activate. It contains info about your mobo, cpu and some other little things like Video Card and RAM.
Now if you install on teh same machine but switch RAM or Video Card the activation will go thru. But if the CPU or Mobo, mobo being the main one, doesnt match that of what is on record for Microsoft to be the system in use then you will have to call them and give them a reason why you are installing Windows on a new machine.
You can reinstall Windows on the same hardware as many times as you want and never have to call to activate.