OK, I have to set the screen saver to come on in the minimum time, one minute.

Now I have to wait a whole minute to see if it works.

Sending Right Shift key works! The screen saver stops!

But what the hell... "Stick-keys"?!? In Windows pressing shift 5 times asks to turn on sticky keys. :( Is it because the come too fast? No, any 5 in a row will do it, even separated by 10 seconds.

Today I thought of the solution! Alternate right and left shift! This fools Windows and no sticky keys dialog!