Ok, here are my specs
Also ram is 4,00 (3,86 usable)

so i will not have lag problems if i install Windows 10 Pro (I have 60 gb left and 4,00 Gb RAM)

I have 4gb ram so I guess it'll not lag.

Sooo if I have 60 gb left and i install windows 10 would it be slow?

Thanks!

Because i've heard that if you have ultimate you will get pro edition. But it says I need sp1.
So do I actually need sp1 or I can just upgrade from ultimate to pro?

Um... I was talking about if I can install Windows 7 sp1, then install windows 10 afterwards,

And can i install windows 7 sp1 on local disk D too?

So that means it'll work just fine?

I'm asking this because this problem occurred once on my PC and it was VERY laggy, and I needed to uninstall one of them wich was very hard.
And if anyone can respond to this thanks!