Im not sure window 10 will run smoothly on my pc
As @
JCgames said, it will run—but there won't be much room left over for running other stuff.
Minimize software which wants to start at boot time—Task Manager, Startup tab—and close down each app when you're finished with it. To play a game, close all other apps first.
You will probably have slow loading times, unless you have a SSD. Windows will use your hard disk to store some current stuff in, and the loading from and storing to a HD will take time.