Video Card Problem

Here is my system specs I have a problem with a graphics card installation.

Coolermaster Sileo 500 Case - *QUIET PC*
Gigabyte GA-EX58-UD5 Motherboard
Intel® Core™ i7 950 3.06GHz
Corsair 750Watt PSU
Zalman CNPS10X Extreme Cooler - *QUIET PC*
Corsair XMS3 6GB (3x2GB) DDR3 1600MHz
1TB 7200RPM SATA II
1TB 7200RPM SATA II
22x DVD RW Black SATA
Internal Blu-ray Re-Writer Disc/DVD/CD Combo Drive
nVidia GeForce GTX 295 1792MB
Microsoft Windows® 7 Ultimate 64-bit
22" Widescreen TFT 1680x1050 5m/s Monitor
Creative Sound Blaster X-Fi Titanium
802.11g WiFi PCI adapter
Internal Card Reader 26 in 1

I wanted to put my pc through my 42” tv and bought a hdmi cable. This cable stretched right round the room, however when I came to connect the cable my nVidia GeForce GTX 295 1792MB card did not have hdmi capabilities no hdmi socket on the back of the card and I thought it did! ( I am disabled and I could not look at the back of the pc because it is hard to get at it.}
I decided to get a new card with a hdmi socket on the back. I bought another card EXACTLY THE SAME MODEL (with hdmi) and proceeded to fit it. Everything went fine until boot up. Nothing on the screen at all, it was totally black. The motherboard made a long beep and two short bleeps. Looking in the motherboard manual this meant there was a graphics problem. I took the card out and sent it back.

I put my old card (same model) back in the pc making sure I connected the internal power cables and booted up. The same thing happened again with my old card which was working before!!

I had an old card (gforce 7300le) which I fit into the same pci express slot as I used for the new card and it worked ok.

I sent for yet another nVidia GeForce GTX 295 1792MB card, it came today and I tried again with the same not working result, so the 7300le is back in!!

I am at my wits end, I have no idea why its done this with 3 cards yet my older card works, I can only think that its something I am missing, its not the pci express slot as my older card works fine.

Please help.... Thank You very much. I hope I have explained ok