Ok been running SLI for about a week now and yesterday my new cooler came for one of the cards, so I whip out the card, leave the other in and power up the PC so I could still use it whislt fitting the cooler.
Now upon refitting the second card windows cant detect it, odd I thought so I swap the cards around just to check if I had fried one card and find that the other card works fine.
I have checked the SLI bridge is in place ok, the SLI switch looks like its set right and both cards are plugged into the PSU

So not sure what the problem is?

Windows just doenst seem to be able to recodnise the second card for some reson.