New Hard drive Question

I installed a 1TB segate in my XP computer to install W7 on when it gets to me Monday. XP is on a 500 gig hard drive. Partioned the seagate and there is some space at the beggining of it that wont partition, just a few gigs. Is that OK? Also, with W7 on its own drive could you take that drive out and install it in a new computer and have everything work. Thanks for your help.
The extra space in the beginning is fine.

You really can't take *any* Windows from one PC and put it in another and have it work. It's very sensitive to changes in the hardware.