I had a similar problem twice: once it was the processor and there was no solution rather than replacing it. It was an AMD 4200+, so it doesn't seem to be the case here.
Second time (another machine) was patience, I had to wait ~20 minutes or half an hour until anything happened. Then the installation continued normally. I am not saying it always happens, I have seen several ppl saying it gets stuck there forever, but it might be worth trying to just wait a bit.