Install 6.5 w/o discs

Cubase
1

My C7 is behaving av bit odd, and id like to try out the 6 or 6.5

is 6 and 6.5 almost same code? Which one is considered most stable?

AND

can i install directly from steinberg.com or do i need a optical drive?

Emil

2

I think Cubase 6.5.4 it is very stable.