Did you upgrade your LR5 catalog during the installation process?
If so all the settings should be the same.
I did upgrade the master catalog during the installation. would the display on the monitor have a big impact on lightroom?
Just a wild guess but, by any chance, were you using custom camera profiles (as made by Adobe DNG profile editor of X-Rite software) that you forgot to include in the new installation. In case a profile is missing, LR defaults to a standard profile (without warning, I believe), and it can make a big difference in the photos.