[Solved] Help! Having problems upgrading my prebuilt!!

Having big Problems upgrading my prebuilt gateway PC. About a week ago the Video Card burned out possibly from the cheap 400 watt power supply. These are my computers currents specs --


Processor -- Intel® Core™2 Quad Processor1 Q9300 (2.50GHz,1333MHz FSB,
6MB L2 cache)

Operating System -- Genuine Windows Vista® Home Premium (64-bit) SP1

Memory -- 4096MB 667MHz PC5300 Dual-Channel DDR2 SDRAM (2-2048MB modules)2

Hard Drive -- 640GB 7200rpm Serial ATA II Hard Drive3 (2-320GB)

Video -- NVIDIA® GeForce® 8800GT 512MB Factory Overclocked (Dual DVI, VGA
adapter and TV Out) (CURRENTLY DAMAGED)

Motherboard -- Systemboard with Intel® G33 Chipset

Operating System Backup Media -- Genuine Windows Vista® Home Premium Media (64-bit)

Optical Drive -- 18X DVD+/-R/RW SuperMulti Drive featuring Labelflash™ Technology7

Power Supply -- 400-Watt Power Supply



Resolution -- 1900 x 1200

Primary use -- Gaming, Movies, Music.



The problem I'm having now is that I purchased two different 1 gig cards one was this one --

Galaxy 55NGH8HX4NXK GeForce GTX 550 Ti (Fermi) 1GB 192-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
http://www.newegg.com/Product/Prod [...] -_-Product

And the performance was horrible pretty much unplayable. I guess my question is.. could it be the power sources lack of wattage that is causing this card to under perform?

Or should I be sticking with another 512 MB card and also upgrade my power source?

I have these items picked out but I'm really unsure about getting something else that doesn't work again.

ASUS CuCore Series EAH5770 CuCore/2DI/1GD5 Radeon HD 5770 1GB 128-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card - http://www.newegg.com/Product/Prod [...] 6814121363

Rosewill Green Series RG700-S12 700W Continuous @40°C,80 PLUS Certified,Single 12V Rail,Active PFC"Compatible with Core i7, i5" Power Supply -- http://www.newegg.com/Product/Prod [...] 6817182191



Any help would be much appreciated thanks a lot.

OHH good idea moto. But the price goes up quite a bit if we go CX 500 and something like a GTX 460 or 6870...

Rompar, how much do you have to spend?

I thought it went 6870>6850>460 1GB>6790>5770/550>450?

And how is the CX cheaper? It's $60 on newegg, the antec 380 is $35.....

I meant $10 cheaper than the rosewill psu Op linked, not yours
the 460 and the 5770 are close approximations, the 460 beats 5770 is a lot of stuff but the 5770 beats the 460 on others,
its back to the old 'which brand does my game like more?' question
I'd say get the new psu Op and that should sort out the Fermi's issues, if not you have time to save up for a newer card and you have the psu to power it for sure

Moto