Four months suffered and still NO solution (alienware x51)

Hi

I am really disappointed. I bought alienware x51 from UK. I heard it is a powerful PC, but I never tested it even thought i have it! Since I bought it 4 months ago, I have a problem with it. I contacted dell technical support and still no solution. They replaced every parts and my PC still not working properly. The screen disconnect suddenly. After they did all the diagnostic to my PC, they told me it needs to be swapped, but because you are in different country now, we can only keep sending you parts and we cannot swap it for you even though you have your warranty!

It doesn't make any sense they knew my PC not working and they offer me parts and i have a worldwide warranty. How come I only can swap it from UK even though i purchased an expensive worldwide warranty. i need a solution or a refund.

This issue starts to effect my time and the image of your brand, so please help me to solve this matter ASAP.