Today, a veteran uncle at my work approached me and told me this:

I’ve got a Windows XP CD. My PC has got Windows 95 installed. Can I upgrade it to Windows XP?

I told him that minimum requirements for Windows XP are higher than Windows 95’s. He accepted the fact.

But, he asked me another question:

If I can install, can I just insert the disk and go!?

I shook my head. Sad… Uncle! It is probable in Leopard only.