Placing O.S on HDD on to new Computer?

[yugimon121]

Ok so I am building a new computer, no HDD in it at the moment.
I got this other computer, which has Windows 7, games etc. on the hardrive.
If i place this into my pc will it load normally with Win 7 or are there other things i must do?

 

[zooted]

You are going to have to re install windows.