Users who have downloaded and installed Windows 8 CP must have noticed a small watermark in the bottom-right corner saying "Windows 8 Consumer Preview Evaluation Copy. Build 8250", though it doesn't take much space but some users might find it annoying.
If you’re one of those users who find it annoying and would like to remove it, then here's how you can remove it.
Head over to this link here and download My WCP Watermark Editor. Just run the tool and remove the watermark. Whole process would take around two minutes and upon completion would ask for restart.
Just reboot and change the background.