Has the Bitcoin network surpassed the total computing capacity of all the general purpose computers in the world?
The comparison doesn't make sense. You can't use Bitcoin ASICs to do general computation, and using CPUs to mine Bitcoin is incredibly inefficient.

It also isn't meaningful in terms of security: no one would try to attack Bitcoin by taking over all of the CPUs in the world. Instead, they would fabricate or buy mining ASICs. (Or, more likely, try to hack into the pool servers that miners get their work from.)