I fitted an additional power cable between my OCZ 700w psu and a second graphics card on my IP Pro35 MB and then the pc would not start up. When I press the on button, all the fans spin for about a second or two and then stop. There is also a beep at the same time. About every 5 seconds it automatically tries again and again to power up but with the same result.

I removed this extra cable so the pc was back to the original setup where it was previously ok and got the same result. I then removed each power lead in turn from the 6-pin sockets in the back of the psu so that I was left with just the internal power lead going to the MB and it still will not start. There is definitely power going to the MB as there are red LED lights on all the time and the green code numbers are showing. When it tries to start this shows a code value of 99 briefly for a second or so.

I'm not sure how by fitting this power cable that I could have caused any damage to the MB?

Any ideas please as I am stuffed without my pc and can't access my data.