Installing Windows 7 on new computer

I'm building a computer but I don't have the Windows 7 yet. I do have a Windows 7 but I've used it. If I install it onto the new computer then will it work until the new Windows 7 gets here to activate it? (You have 30 days to activate it, right?)

 

There is no reason for it not to work for the 30 day activation period.
You need to be aware that if you install this earlier version it will use a lot of bandwidth to update itself and if you are on limited bandwidth you need to consider this.

For me personally i would run with this early version until the new one arrives and then install the new version but that is just me.

 

One other thing I would mention is if the Windows you install is different than the one you are waiting for, the key will not work. Different keys are used for OEM, retail, Home Premium, Pro, and Ultimate.

 

I believe they are the same:

OEM system builder pack
Windows 7 Home
64-bit

But since I'm not a pro I'm afraid I'm missing something. The computer is for my son and he is very anxious for it but the new Windows won't be here for another 5 days. I would really hate for him to get his new software on here then have to completely reformat if it doesn't work so I'm just a little scared to try it. :/

Thank you both for the input!