I assume you installed Windows 7 twice to the same hard drive? If so, you may want to watch out because the bootloader may be on that first (smaller) partition. You can check this by seeing if there is a <drive letter>:\boot folder in the drive. If the smaller partition has the \boot and the larger one does not, you may be better off doing the install again, or you'll have to try to restore the bootloader (an activity that I fail 50% of the time ).
You may be in luck if the installer gave you the little 100-200MB partition at the beginning of the drive, in that case the bootloader is there and you shouldn't have issues.
In either case, I'd back up everything before trying to mess with this, or you can end up destroying both installs.
__________________ "The computer programmer says they should drive the car around the block and see if the tire fixes itself." [src]