I thought I had responded to this, guess not.
Anyways, I used to have this problem and determined it to be graphics related, as at that time, my vid card was 4 years old and it just couldn't run the game like it could before (right after the update to 3.12 I think) Any way, symptoms were, random freezing, if I clicked, it would display an hour glass, letting it go didn't do anything as after 15 minutes it still was hung up, etc, etc. I found it to be that it would freeze while it had to wait for my vid card to process what it needed to be displaying but never got caught up and so it just hung. I had to lower the setttings down in pssetup and they went away. I changed the texture downsampling from a 1/1 to 1/4 ratio, and the problems went away.
It may be that when it freezes you are having the same types of problems. I'd suggest try to play around with the options to see what happens.