What is the difference between Protestantism vs Protestants? According to me Protestants are the one who doesn't pray to Mary.

I also came across the Protestantism which speaks about the 95 Theses which Martin Luther started against indulgence. 

I don't see any relationship with Protestants and Protestantism. Are they same? Or Protestants came from Protestantism?

Rectify me if Iam wrong.
"Protestantism" is the name of a movement. "Protestants" are people who are part of that movement. It's the same relationship as between the words "Catholicism" and "Catholics". Catholics are the people who are part of Catholicism.

The problem is that your definition of Protestants is far too narrow. Protestants don't pray to Mary (mostly - there are a few exceptions) but it's not the most important thing about them - there are many other differences between them and Catholics too - their beliefs about the authority of the church, the place of the sacraments, the theology of the priesthood are just a few of many examples. It should also be pointed out the Protestantism is incredibly diverse and there is almost nothing that is unquestionably true of all Protestants except that they are not Catholic (or Orthodox, whose followers are also considered not Protestant).