Fresh OS Install and Partiationing Drives

[gongchime]

I saw one optimization guide said to do a fresh install of the operating system as I had done with my old desktop. My new laptop didn't come with a disk containing the operating system though. People in the computer shops are saying I can load the operating system I already have by copying it to DVD then reinstalling it. Where would I find the registration code number in that case? Is that advice bunk or is it tha I don't need the registration number again for a clean install? Recap: What should I do about a fresh install of the OS?

I bought another version of Windows Vista Permium just like my laptop currently has. Can I use that if it's legit? I haven't looked at whats on the disk yet but it doesn't have the gold laser fraud prevention image on the exterior. If I see a "crack" file when I look inside it I'll suspect it's worthless to me. They said they didn't have the original in stock. Their reason is because it's obsolete and Windows 7 is what people want now. I still think a version of the OS should have come with my laptop and believe they removed it so as to resell it. Recap: Can I use another theorhetically identical version of the OS if it's legit?

How do I partiation the drives and do I do this during the fresh install of the OS? In one of the optimazation guides it said to "click on the drive in question" then make sure that compress this drive is unchecked" etc... When it says "drive in question" does that mean only one of the drives should have this process done to it and if so which one? Or does it mean I should do it to both of them? Recap: How do I partition the drives?

Thanks,