How to know correct video drivers ?

[Chris Jones]

>> I was suspecting that may be some new drivers needs to be installed and
>> I enter the software maze of "X.org", but I don't know what to select
>> from there.
> 
> For direct rendering you need the proprietary Nvidia driver. See 
> <https://help.ubuntu.com/community/BinaryDriverHowto/Nvidia> for details.

I the OP has not actually said what video card they have. You are 
assuming here they have an nvidia card.

I would start here instead

https://help.ubuntu.com/community/BinaryDriverHowto

I choose the instructions accordingly

Chris