How do I play high quality films on my HP Compaq computer?

When I play big file films eg 2 GB then the quality is shaky, its not smooth, its only smooth if I play a file smaller than 1 GB. Why is this, how do I play big files for the best quality? I've tried ALShow, Gom Player, VLC player but none of these play high quality films. Please help! Thanks.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).