"Tried the file check program"
Did it indicate any changed files that may have become corrupt?
"Install the game. Able to play it, save it and quit the game. Using save or quicksave is making it freeze on reload."
If you play for a couple minutes and quit without saving, do you have the same problem?
"I've removed the savegames and deleted the dynamic directory. Then it would start up fine or sometimes not"
Is it freezing when the game itself is loading, or when loading a save?
Do try the memory and hard drive tests.
