I have this problem i don't know how to fix. I have a AMD Athlon x4 860k Quad core processor and it only shows 1 core and 2 logical cores. In device manager i can see all four cores. And i even tried msconfig, boot and advanced options there i could only select 1 or 2. I checked UEFI and there i could see all four cores as well but i dont know if they are enabled. Please let me know how to fix. Thanks.