I have decided to format the laptop I bought last year. It is a Sony VAIO VPCSB Series.
It shipped with Windows 7 Professional, but now I want to install Windows 7 Home Premium on it. So I did it, formatted the HD and installed the new OS. Once I was done, I noticed the laptop was very, very slow, despite the fact that the OS was clean. The next day, I turned the computer on and this time it was just fine. That made me suspicious and led to the question.
Would it be better to install Windows 7 Pro? Is this a known and common issue when installing a different version of Windows on a laptop?