Well, the huge difference between Windows 95 and Windows 2000 is
that since Windows 95 is five years older than Windows 2000 Windows
95 is on the lower end of the scale of revolutionary
technology.
Another big thing is the startup sound's origins of the two
OSes.
Windows 95s startup sound was made (ironically) by someone on a
MAC, while Windows 2000s was made on a cheap piano....
Windows 95 was missing a lot of tools used on Windows 2000, and
one huge one was USB support.
See, Windows 95 needs an add-on for it to support USB, while
Windows 2000 came with support standard. But then again, did USB
even exist in 1995?
Another big fact is that the two OSes are targeted at different
parts of life: 95 is targeted for educational and home use while
Windows 2000 is a "Professional" (buisiness-targeted) OS. But
Microsoft also created a (unstable) home version of 2000 dubbed
Millennium Edition. (Millennium Edition is commonly known as
ME)