After about half an hour, my win764 bit ultimate freezes up and I have to restart. Can I fix this?

Hi, When did the issue begin to occur? Have any new programs or hardware installed on the machine? To troubleshoot the issue, I suggest you restart the machine in Safe Mode and check whether the system still freezes or not. If so, please let me know. Otherwise, I suggest you restart the machine and perform a Clean Boot to check the result. Thanks, Novak

Any chance you're using MS office? Or a Sharepoint server? How about OneNote? My system always freezes when I do that. Apps go white and the title bar gets "Not Responding" Appended to it.