i have Acer laptop and the problem am facing in the laptop from the beginning is with its display.firstly when i start the laptop it dosent starts properly so when i shake the screen then it starts.later while working on it suddenly it hangs for a second and there is no display.nothing will be shown on sreen it goes black.some times it runs well and some time it shows same problem.now what to do for the solution.please help me out.

having to shake a laptop to get it to function is not good ,it needs to be taken apart and checked for bad connection ,and broken parts ,good luck

The power connector that plugs into the laptop, does it feel loose when plugged in?

Sometimes, because the laptop hinge is very close to the power connector, when you open the laptop it can appear to be a fault related to the opening of the laptop, but often that isn't the case. Over time the power connector becomes loose due to use.

Which model laptop is this, please?

don't compromise with ur machinary. like u have discovered a short term method to recover ur laptop e.g. shaking it.

frst u need to know whts wrong with its hardware.