Change display language to a one which does not officially support (Windows Vista / Windows 7)

Recently one of my neighbors who visited Italy brought a Laptop. The operating system was an international version of Windows Vista Home Premium and the display language was in Italian. He wanted me to change its language into English. Both of us didn’t know even a single word in Italian language. I hardly managed to find the “Region and Language” settings in control panel and tried to change display language to English. Daaa... English was not there to select. I did a browse through the internet to find a solution but some of the postings discouraged me as they say it’s impossible. Finally I found this tool called Vistalizator and was able to install English Language Pack for Multiple User Interface (MUI) with the help of this tool. Set of screens of an installation walk-through is also available.