screen keeps jerking and there are automatic touches First of Tablet info : 

Model number : Micromax P275

Android version : 4.0.4

Baseband version : v3.0

Kernal version : 3.0.8+ linda@SKYWORTHSERVER3 #52 
Fri Sep 21 14:00:53 CST 2012

Build number : P275_HW.V0.1_V3.0_20120921

I dont know anything about android

now the issue is that the screen keeps randomly jerking and there are random touches that happen which will open apps and close apps randomly. this happens after few minutes since  Tablet turn on. When these things happen i cannot do anything. even if i try to power down by pressing the power key the dialog box disappears because of this random behavior.

i observer this behavior mainly when i travel in bus. so i'm thinking that the vibrations are affecting the accelerometer and thus causing the random movements. When i'm in a stationary place i rarely see this issue, but it has occured.

now i disabled

1)Auto rotate

2)Disabled all options in Developer options except Force hardware rendering.

the system update will happen and i cant turn it off(atleast i dont know).

my main useage in the Tablet are 1) pdf reading 2)videos 3)small c programmin(using CCtools).

please help me with this issue. its is very very frustrating. last thing,i brought this device 28 days ago. also i would like links on reinstalling android.
From your description, there are two obvious possibilities. The first is that some static electricity or oil on the touch screen is causing it to think you're touching it. Try giving the screen a good wipe. Also, earth yourself by holding a metal water pipe with one hand, and cover the screen with your other hand.

The alternative is a manufacturing defect in the touch screen. Faulty touch screens are quite a common problem with cheaper tablets. If you can manage to do this with all the false touches, try to install a paint program from Google Play and run it on your tablet. Leave the paint program running for a few minutes, and any false touches will paint on the screen. You can see where they are happening. You may see a pattern to them, such as all being in one strip of the screen, or always at one point. That would confirm that it's a fault in the touch screen, in which case you should return your tablet and get it replaced.