The original RTM version of Windows 7 is Build 7600. What you have with it showing Build 7601 is SP1. As SP1 is still in Beta and therefore still being tested and evaluated, you will see the watermark at the bottom right of the desktop. Just to verify this, click Start
and type winver
and press enter/return. Do you see this?
There is one thing that is puzzling me though. You said that this was a new reinstallation. As of yet, I am not aware of any versions of Windows 7 with SP1 pre-integrated. Have you installed SP1 (Service Pack 1) separately?