quiet cases?

My PC is a few years old now and I've been looking into upgrading the graphics card, but at the same time change the case. At the moment my HP M9070 is unbelivebly noisy. The two front 'flaps' that conceal the usb/audio outputs and the hp backup intake air and seems to hit its resonant frequency. To try and stop this i've been wedging peices of card in the gaps. But seeing as I'm messing arount with it I might as well get a new quiet case.

Anyone know what case would be best?
I'm looking at spending around £20-60 but I'm a little flexible.

Thanks

Sorry to sound like a bit of an idiot but this is my first upgrade and I'm starting to confuse myself!
With graphics cards, the specification from the hp website says I have:

GeForce 8500GT

· 512 MB GDDR2 memory

· I/O Ports: HDMI, dual-link DVI , S-video

I've been looking a graphics cards and some of them need 2 pins from a power supply?! I don't even know what that means!
Can anyone surgest a good graphics card that I can just slip in the place of the old one. I don't think I have enough skill to mess around with the power! Or do I need to mess around with the power to get a decent graphics card?!

Do I need to mess around with the power to get enough cooling in another case, or so I buy a case with fans or just put my old fans in?

Major headache :/