New GPU, new problem.

[Mecha]

I've decided to upgrade my PC on the cheap by buying a graphics card (AMD Radeon HD5450 from XFX) and more RAM (two modules, 1GB each, no specified brand) from eBay because I'm slowly growing tired of the low gaming performance. I received the graphics card just today and now I have this problem:

if I put the new graphics card in the slot and boot up, there is only a black screen, all internal fans go maximum rotation speed constantly and is stuck in this state forever until I manually cut off the power. There are no beeping sounds and lacks in any kind of audible and visual feedback. If I put my old graphics card (ATi Radeon X600) back in the slot, everything works fine obviously after installing the old drivers.
I did uninstall the old graphic drivers before performing the upgrade and double-checked the card itself of any damages, there are none.

PC specs:
CPU: AMD Athlon 64 X2 4200+
RAM: 2x 512 MB RAM Dual Channel, DDR1 PC3200 @ 200 Mhz, brand: Samsung
(Current) GPU: ATi Radeon X600 256MB
Mainboard: MS-7093
Power Supply: 300W NoName product
BIOS: Phoenix Award 6.00PG
Sound: Realtec AC97
OS: WinXP SP3

What causes this problem? And what can I do to solve it? By the way, the new RAM should arrive within this weekend.

[iRobot]

Did you connect all the power connectors to the graphics card?

[Mecha]

It has none because of low-profile design and uses a fanless heatsink.

[LiZaT]

You have not enough Power at Startup, or the Graphiccard is broken.

[Pinky]

No, power consumption looks fine to me.
I rather suspect an incompatibly between your motherboard's BIOS and the graphics card. After all, your ATI card is muuuch younger than your motherboard. You could try to look for a BIOS update - but I wouldn't expect that a new one has been released in the last years given the age your mainboard...

[Aberiu]

300W NoName

This might be the reason. Especially if it's 5 or more years old.

[Pinky]

if it would be a power consumption problem, the power supply unit would automatically do a safety shut-down (or blow up)...

[SageOfSixPaths]

Just to be sure, have you plugged the 12v atx cable in?

[Mecha]

Everything that's necessary are plugged in their correct places. My guess is that Aberiu is right with the power supply problem. The entire system except the CPU is nine years old after all, the capacitators must've aged really well.

[Calypto]

If it were a power supply problem, then indeed it would shut off or fry everything. Did you try re-seating it?

In addition to this thread, here is another:
http://www.techpowerup.com/forums/threa ... lp.167473/

And if all else fails, an article regarding its power consumption:
http://www.guru3d.com/articles_pages/ra ... iew,6.html