Hi
 
I just put in my second GTX 560 Ti yesterday and it boot up fine and everything was okay. I boot my computer up this morning and the resolution is low and I go into device manager and both cards have Error 43.
I can disable the cards and then enable them and everything is fine again and I can access the Nvidia control panel. If I restart my computer then everything is still fine when it boots up, but when I completely power down and turn back on I get an Error 43 on the cards until I disable and enable them again. 
 
Anybody know why that is? I have latest drivers and did a clean install of the drivers when I put the new card in. I have Windows 7.

The the last beta driver and see if there is any change.  When installing just enable the clean install option under Custom after the drivers uncompress and it will remove the current drivers and settings before putting in the beta.  You can download them here.