You should realize, unisol, that Windows 7 is built on Vista - at least for now it is. So, expecting it to *not* mess up your system is pretty far fetched - considering that I manage 2 labs at school running Vista, and have been using Vista at home, and the only time I had *anything* mess up was when I replaced me mobo with a different one and expected Vista to play nice.
Can you detail exactly what Vista did to your system(s)?