Windows NT License

we have around IBM 40 PC in our company bundle with W2K Prodessioanl License each. Since our application problem, we have downgrade to Windows NT and cloned with same image, thus we have the same License key information on each PC but we have different paper license for each PC. I wonder is there a legal issue under such environment in our company. Or is there a way we can change our PC license infromation. Thanks!