You might have just as well said "I just bought a new car, can someone tell me if it has leather seats?"
OS version and updates AE version, and some kind of detail about what is in the Layer Panel when it freezes. Otherwise we can only guess and my guess is that you have some incompatible footage in the layer panel or you're running out of memory, or your MP and memory settings are off, or your Disk Cache is full, or . . .
Running Windows 7 and AE6 is version 188.8.131.52 and I'm on the Cloud so it stays up to date.
We have two identical suites and we just tested the other one with the same results. The Layer window freezes AE whenever I dock it with the Comp window. I can dock Layers with any other window and I can dock any other window with the Comp window and they work fine...but for some reason the Layer and Comp windows don't play nice together.
I have tested it in old projects, new projects, with footage, without footage, in my personal workspace, in the AE workspace options. I keep my system pretty clean when it comes to memory so that isn't an issue. Plus, the other system rarely ever runs AE so that nulifies the memory option.