I am running CS5 and Win 7 64 bit. I have experenced crashes when I try to open a file, and sometimes when I try to save a file. I always get a message thet the system is not responding, and I can either close or check the web for a solution, then close. I have gotten into the habit of saving my file every several minutes. Usually when I restart Photoshop, it is OK for a while, but then the crashes start again.
No big deal, but certainly inconvenient.