Hello cahaseler,
If you use the restore disks that came with your computer, your Vista should not require Activation. The Office product will need to be reactivated, when you open one of the Office Products, it should prompt you to activate, if there are no problems, it should reactivate over the internet in a few secs.
The reason your Vista won't need to be reactivated is that computers, which are built by large manufactures that come with Vista Pre-Installed, come with two (2) Product Keys:
A) OEM SLP: This key comes pre-installed in Vista, when it comes from the Factory. This key is geared to work with the special instructions found only on that Manufacturer's computer hardware. So when Vista was installed using the OEM SLP key (at the factory) Vista looks at the motherboard and sees the special instructions and Self-Activates. (that's why you did not need to Activate your computer after you brought it home)
B) COA SLP: This is the Product key that you see on the sticker on the side (or bottom) of your computer. It is a valid product key, but should only be used in limited situations. The key must be activated by Phone. (Note: All manufacturers that use the OEM SLP system are required by contract to include a Certificate of Authenticity (COA) sticker, that has a COA SLP key, on the computer)
The restore disks that come with the computer will reimage the hard drive just as it was when it left the factory, including the OEM SLP key.
If your Vista ever asks to be Activated, you know that (for whatever reason) the OEM SLP's self-activation process as failed. To resolve that issue, change out that OEM SLP product Key for the COA SLP key and then you must use the Activate by Phone method (and must talk to a Live Activation Rep, not the automatic Voice prompt), to Activate.
Hope that helps,
Darin MS