sprite draw is suddenly broken for me

Everything was fine 3 days ago, but now both my exercises with pixel engine and glhf demo show the same problem: no errors, windows is created and even filled with Clear color, but no sprites is drawed. Window updates and closes just fine, draw method is called, but no evidence off sprite

what i'm doing wrong?

win7 x64, Nvidia last drivers.
Sry for mb stupid question!