Which is the best windows 7 tweek software? Help me… 
What are you trying to do ? What changes do you want to make ?
all the admistrative chalges
I don’t run Windows 7, but it looks like you can fire up the group policy editor by bringing up the run box and entering “gpedit.msc” (no quotes).
I usually suggest not to use any tweaking software. That’s because I’ve had some bad experience with them. Like Big B said, use the things that windows supplies, like msconfic, services.msc etc (for a more, let’s say, comprehensive list, check out this site)
I would not suggest turning off everything, I have turned off just a few without any problems.