After days dealing with Windows 7, I finally decided to just reinstall the Original OS in English (mine is Japanese version). Then I asked myself if Is Windows 7 really worth tweaking for Vaio Type P? I recently installed Windows 7 on my P91HS, and speed is really impressive, compared to the pre-installed Vista. But, after I installed antivirus(just it), it started to slow down, plus the screen doesn't refresh much, leaving black squares that needs to be unshrouded. (this is because the device drivers is not intentionally for Windows 7). I'm not sure on windows XP, but windows 7 gets really slow after installing something. So, I am considering to just use Vista (English one, because I have pre-installed Japanese). Having the pre-installed and clean install partition by partition .
You can see that the result nearly matches the speed of fresh installed Windows 7. That's because there are no other services to load, but the real thing can be proven when you installed all the applications that you use.
Instead of installing other OS(es), I'll just install some applications first, especially those that I frequently use. You might say installing Visual Studio on Type P is useless, but let's check on that one.