Sorry that you're seeing problems.
These two guides are usually a good place to start, depending on when the freezes occur:
[ul][li]Crash, exit or high CPU usage when viewing certain directories[/li]
[li]Crash, exit or high CPU usage when right-clicking certain files[/li][/ul]
There are also some general suggestions of things to try, starting with easy things and moving through to more time-consuming ones, here:
[ul][li]General slowdown or instability investigation steps[/li][/ul]