Nvidia 280 GTX - Problems putting it in computer [HELP]

Hey all,

I'm putting a 280GTX into my computer. At first I thought it was a 285GTX (my friends giving it to me for free, he got a free one from Dell) but realized from its power cables, it requires a 6 and an 8 pin connector while I googled the 285GTX and it needs 2x6pin, meaning mine must be a 280GTX, probably a mistake from my friend (unless some 285's had an 8pin?).

Anyways, my problem is that I'd plug in my 6 pin in, and it would snap in perfectly. My 8pin connector, however, did not fit in nicely, and had to be almost forced in, but it WAS 8 pin and so was the slot on the video card so I didn't understand. I went out and bought a Dual Molex to 8pinn connector as I had two molex power cords available inside my computer. This one can get on easier than the last one, but I get the same problem: The computer fails to start up even for a milisecond and the power supply shines a red light next to the switch in the back. I don't know what to do. Someone said trying to start it with a 6 pin in the 8pin compartment but my PC started to beep so I turned it off right away.

ALSO, something very important which might be the entire problem here: When I removed the video card from my friend's dell, there was this thin red cable thats attached to the video card that had plugged into the Dell's motherboard. On my motherboard I can't see a similar spot to plug it into, but here is a link to my mobo, so perhaps you guys can see a screenshot of it and tell me whether or not my motherboard supports it:

http://www.msicomputer.com/product [...] m&class=mb

I really hope someone has a 280GTX and can explain to me what this thin red cable coming out of the video card is for and where it goes into. Its a very thin wire, and the end looks like:

. . .
. .

It has 5 holes in a pattern like that on the end.

THANKS VERY MUCH for any help!

I believe its a Cooler Master 550W, thing is my case is messed so to take out the PS I need to dismantle it. Yeah I know....

It COULD be a thermal take or enermax but im fairly certain its a CM. I can see, however, that it is for SURE a 550W and I remember the box had a thing saying "Built for Nvidia" on the side.

Anyway my neighbour, a computer technician whos on vacation, said that my power supply can support the latest video cards when I told him about the problem but since he's not here and not a specialist on video cards he can't help further. I have 2x6 pin connectors available plus an 8pin from my PS but like I said, my 8 pin doesn't fit in nicely and the adapter im using can fit, but the computer still refuses to turn on.

If the little red cable doesn't matter, then I don't know what it could be.