Dronxa :
I searched a bit and i found that the gtx 660 takes 150 W when running can I use it then on a 200w http://www.komplett.se/k/ki.aspx?sku=781928#extra
Yes a GTX660 needs 150watt. An other around 100watt is needed (at least) by the rest of the system + the CPU. Not to mention the GTX660 needs 1 PCI-E 6pin. Well you can do the job with CX430 too (which is cheaper but you are limited to 1x PCI-E GPUs).
Anyway the point is that the PSUs these desktops have, are too weak to support a good GPU. That's probably why I haven't see any good and cheap gaming build. They prioritize looks from performance :S on a gaming build... Just no comment...
So either take Packard Bell L4875 and place a CX430 + GTX660 or, look for other websites too
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(IF you are going to look on other sites, just be sure the gaming PC to have: For CPU: i5 2xxx, 3xxx, 4xxx, For RAM: 8GB, and for GPU: GTX 660 or more or any AMD equal.)