I have tried both the 257.21, and the 258.61 drivers, and neither have the option to enable SLI.  I have reinstalled using driver sweeper, and still nothing.  I did some searching on the net and read a few places that suggested that the Realtek LAN drivers for my mobo might be interfering.  Has anyone else seen this?

I an useing the 258.96 driver with no problems i have used though drivers in qustion with no problems.there is not much i can say but do a driver sweep.

Awesome, glad it worked out for ya and thanks for the BR!

As for coming late, no worries, better late than never and it should be like adding a turbo charger for your 260s in SLI!

hmm... no dice for me :(

Wednesday I got 2 SSD's that I hooked up in RAID 0.  I did a fresh install of Win 7 64 Ultimate on them and have been happy with them until today.  I locked up this morning and that was that.  

I figured I got a bum SSD and swapped my old HDD back in.  I fired it back up and continually locked up at the Windows loading screen.  So now I'm starting to think it's not the new SSD's after all.  So I pulled out my old P55 SLI and swapped everything over.  Same thing :(.  I even tried swapping out the RAM.

Then I figured it must be my CPU.  I went down to Frys and picked up a new i7 870 and brought it home and popped it into my P55 FTW mobo.  Same deal, would lock-up at the Windows loading screen :(.  Next I tried it in the P55 SLI and everything fired up.  Once Windows booted it started automatically downloading and updating drivers.  It asked me to restart, which I did and came back to find my SLI settings had completely disappeared!  They were there this morning, what the hell.....

So now I've done everything I can think of except reinstalling Windows.  I've run driver sweeper in safe mode and reinstalled, I've tried older drivers, I've tried the above network driver.  Both cards are recognized as I have 3 screens and they all working as normal.  The only thing out of the ordinary is that the Physx/SLI tab under 3d settings now reads Physx only and I have no way of enabling Physx or 3D Surround 

Thank God for this sticky!  I have never had this problem until today.  Upgraded the 260.63 drivers to 260.89 and got a little worried when there was no SLI option in the control panel.  I restarted my computer, reinstalled the drivers, but no SLI.
 
I was getting really mad and was coming on here to make a thread when I saw this one thankfully.  Downloaded the file that Chizow put up and installed.  Restarted my computer and could select SLI again!
 
So thanks Chizow for that fix!