The "CPU: NO" bug has been fixed, so you shouldn't need to use that anymore.
However, some people still aren't getting GPU work no matter what they do. Anecdotally, it seems that everyone still having problems has a 400-series Fermi card, although some people with Fermis are getting work.
This isn't a case of no work being available. You should be getting work, but aren't for some as yet unknown reason.
One thing to check for on your end is that either the PPS Sieve application is selected or the "Allow other applications" box is checked.
Another thing to try is to make sure both the "default" location and whatever location you're using (home, school, work) both have the correct settings for sending work to the GPU. If you're using the default location, try setting up a different location for this machine. This might or might not help. It shouldn't make a difference, but I've personally seen some odd behavior with this in the past, so it might be worth trying.
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