To capture screen on a Lenovo A369i and many other Android devices, press "Power" key & "Volume Down" key simultaneously and hold for a second or so. You will hear a sound and the screen shot will be saved.
A short difference of few milli seconds between pressing these keys doesn't matter, but the difference should not be so much that the power down function or volume down function are activated.
This works for many Android devices. For some Samsung devices I've seen a swipe from one edge of the screen to the other edge takes the screen shot.